Traffic Calming is the systematic application of engineered measures designed to reduce vehicle speeds, alter driver behavior, and improve conditions for non-motorized street users. It encompasses physical infrastructure modifications, visual treatments, and access management strategies that prioritize safety, livability, and equitable street space allocation over vehicular throughput. Traffic calming represents a fundamental shift from streets designed solely for vehicle movement to "complete streets" that serve all users—pedestrians, cyclists, public transport passengers, and motorists—within a framework of shared responsibility and reduced risk.

51 MinutesBy Krispin HeathIn Blog03/12/2025

Introduction: The Paradigm Shift in Street Design

For decades, the principal design imperative of our streets has been to maximise throughput: the fastest, most efficient vehicle movement possible. Wide, gently curved lanes, long sightlines and a lack of “obstructions” has become enshrined as best practice. In this view, the street is a pipe through which to channel traffic, performance is measured in vehicles per hour and level of service, and success is a journey time reduction.

Everyone and everything else – pedestrians, cyclists, children, residents – is an afterthought, a traffic “generator” to be tucked behind the cycle lane and out of the way of traffic moving at all speeds.

This way of thinking is starting to fall apart.

Around the world, cities and towns are waking up to the potential of a different vision: The “Living Street”. Spaces where children can play safely; where older people can cross the road without fear; where local shops can flourish because people want to linger and spend rather than fly past at 50mph; where the air is cleaner and quieter because travel by car is slower and walking, cycling and other forms of active travel are not just possible, but safe and attractive. And it’s not just nice to have, but backed up by a growing body of evidence from public health, safety, economics and environmental data.

Traffic calming is at the heart of this movement. It’s both a craft discipline and a strategic approach. It draws on civil engineering and traffic engineering skills, but also psychology, urban design and community development to achieve shared objectives. And when done well, traffic calming is more than just reducing vehicle speeds. It is about redefining the purpose of the street, and who and what the street is for.

This guide is a one-stop-shop for transport engineers, transport planners, highway engineers, local authority officers and community groups who want to find out more. It will cover the evidence base for traffic calming, the engineering toolkit that is available, how to implement measures that work and what the future might hold for traffic calming technologies.

Part 1: The “Why” – The Imperative for Traffic Calming

The Multifaceted Goals of Traffic Calming

Traffic calming is not a single-issue intervention. While speed reduction remains the primary mechanism, the goals extend across multiple domains of public policy and community wellbeing. Understanding this multifaceted nature is essential for building the political will and securing the resources necessary for comprehensive implementation.

Vision Zero and Pedestrian Safety: The Moral Imperative

The statistics are stark and unambiguous. According to the World Health Organization, road traffic injuries are the leading cause of death for children and young adults aged 5-29 years globally, claiming approximately 1.35 million lives annually. In the UK alone, Department for Transport figures show that in 2022, there were 1,695 reported road deaths and 29,742 killed or seriously injured (KSI) casualties.

The relationship between vehicle speed and injury severity is not linear—it’s exponential. Research consistently demonstrates that:

  • At 20 mph (32 km/h), approximately 3% of pedestrians struck by a vehicle will be killed
  • At 30 mph (48 km/h), this rises to 20% fatality risk
  • At 40 mph (64 km/h), the fatality rate exceeds 80%

These figures, validated by Transport Research Laboratory studies and cited extensively in Department for Transport guidance, reveal a brutal truth: small reductions in speed yield disproportionately large improvements in survivability.

The Vision Zero movement, originating in Sweden in 1997 and now adopted by cities worldwide including London, New York, and San Francisco, operates from an ethical starting point: no loss of life is acceptable or inevitable in our transport system. Traffic calming provides the primary engineering toolkit for achieving Vision Zero objectives, particularly in urban environments where vulnerable road users and vehicles share space.

Beyond fatalities, the injury burden is substantial. The UK’s STATS19 data shows that slight injuries, while less catastrophic, impose significant healthcare costs, lost productivity, and diminished quality of life. Traffic calming measures have been shown to reduce injury collisions by 40-60% in treated areas, according to systematic reviews published in the Transportation Research Board’s Highway Safety Manual.

Public Health Benefits: Beyond Collision Prevention

The public health case for traffic calming extends well beyond collision prevention into chronic disease prevention, mental health, and health equity.

Active Transport Enablement: Streets perceived as dangerous suppress walking and cycling. A comprehensive study published in the British Medical Journal found that traffic calming measures increased walking trips by 12-18% and cycling by 15-25% in treated neighborhoods. This modal shift delivers profound health benefits. Regular physical activity reduces cardiovascular disease risk by 30-40%, type 2 diabetes by 30-50%, and all-cause mortality by 20-30%, according to Public Health England guidance.

Air Quality Improvements: While counterintuitive to some, traffic calming generally improves local air quality. Smoother traffic flow at consistent lower speeds produces fewer emissions than the acceleration-deceleration cycles characteristic of higher-speed urban driving. Additionally, by making active transport more attractive, traffic calming reduces vehicle kilometers traveled. Research from King’s College London demonstrates that 20 mph zones in London have contributed to measurable reductions in NO₂ and particulate matter concentrations.

Noise Reduction: Traffic noise is not merely an annoyance—it’s a significant health hazard. The WHO estimates that traffic noise contributes to 12,000 premature deaths annually in Europe through cardiovascular effects and stress-related pathways. Speed reduction from 30 mph to 20 mph typically reduces noise levels by 2-3 dB(A), which represents a perceptible improvement in acoustic environment and measurable health benefits.

Mental Health and Social Cohesion: Streets dominated by fast-moving traffic fragment communities. Research by urban sociologist Donald Appleyard in the 1970s, repeatedly validated since, shows that residents on heavily trafficked streets have fewer social connections, report lower life satisfaction, and experience their homes as less pleasant. Traffic calming creates conditions for spontaneous social interaction, outdoor play, and the development of social capital—all protective factors for mental health.

Community Livability: Reclaiming Public Space

Roads take up 25-30% of land area in our cities: our biggest public asset. High-speed traffic turns this from a public resource into hostile territory.

Traffic calming turns streets into places where:

  • kids can play outside their front door
  • older people can cross the road without fear
  • neighbours can chat without having to shout over cars
  • street trees and sustainable drainage can be installed
  • outdoor cafes and trading are possible

It also makes good business sense. University of Westminster research found that traffic-calmed, pedestrian-prioritised streets experience 40% more retail spend per square metre than those prioritising cars.

Walkers and cyclists make more regular trips and spend more in the long run, even if they spend less per trip than drivers.

Traffic calming is good for house prices too. A series of hedonic pricing studies have found property prices on calmed streets 5-10% higher than similar, through-traffic streets.

Environment & Climate Goals

Transport is responsible for c.27% of UK emissions, with the vast majority from road transport. Traffic calming can support decarbonisation in a number of ways:

  • Modal shift: Traffic calming makes walking & cycling safer & more attractive, reducing VKT
  • Optimising speeds: Cars consistently driven at 20mph use less fuel than stop-start driving at 30-40mph
  • Enabling street trees and SUDs: Traffic calming schemes can & should include measures which increase carbon storage & climate resilience
  • Directly linked to legal duties under the Climate Change Act 2008 & council-level net-zero targets

Part 2: The “What” – A Taxonomy of Traffic Calming Measures

The Engineer’s Toolkit: From Vertical to Horizontal Deflection

Traffic calming measures can be categorized by their primary mechanism of action. Understanding these categories enables engineers to select appropriate interventions matched to specific contexts, constraints, and objectives.

Vertical Deflection Measures: Forcing Speed Reduction Through Geometry

Vertical deflection measures use changes in road surface elevation to create discomfort or vehicle damage risk at excessive speeds, thereby compelling drivers to slow down. These are among the most effective traffic calming tools, with speed reductions of 5-15 mph typically achieved.

Speed Humps (Road Humps):
Speed humps are the most widely deployed vertical deflection measure. Typically 75-100mm in height and 3-4 meters in length (measured in the direction of travel), they create a parabolic or circular profile that generates significant vertical acceleration when traversed at speed.

Technical specifications: UK guidance (Traffic Advisory Leaflet 7/96) specifies maximum heights of 100mm for humps on roads with speed limits of 30 mph or less. Spacing between humps typically ranges from 50-100 meters, with closer spacing producing greater speed reduction but higher implementation costs.

Applications: Speed humps are most appropriate for residential streets, school zones, and areas where sustained speed reduction across extended lengths is required. They are less suitable for bus routes (due to passenger discomfort) or emergency response routes, though these concerns can be mitigated through design modifications.

Materials and construction: Traditional asphalt humps offer durability and relatively low cost but require extended installation time and traffic management. Modern alternatives include:

  • Prefabricated rubber humps: Quick to install, removable for trial schemes, but less durable and prone to displacement
  • Prefabricated concrete humps: Durable and quick to install, but higher initial cost
  • Quicksetts modular systems: Jobling Purser’s Quicksetts technology represents a significant advancement, offering rapid installation (typically 2-4 hours per hump), exceptional durability through high-grade materials, and flexibility for future modification. The modular nature allows precise height adjustment and simplified maintenance compared to monolithic asphalt construction.

Speed Cushions:
Speed cushions are a variant designed to allow wide-axle vehicles (buses, fire engines, ambulances) to straddle them while still affecting cars and motorcycles. They typically consist of two or three raised sections across the carriageway width, with gaps between them.

Technical specifications: Individual cushions are typically 1.7-2.0 meters wide, with 900mm-1000mm gaps between them. Height specifications match standard speed humps (75-100mm).

Applications: Speed cushions are the preferred solution for bus routes and emergency response routes where speed reduction is needed but large vehicle passage must be maintained. However, they are less effective than full-width humps, typically achieving 2-3 mph less speed reduction.

Limitations: Motorcyclists and cyclists may find cushions uncomfortable or hazardous. Some drivers of smaller vehicles learn to straddle cushions, reducing effectiveness over time.

Speed Tables (Raised Junctions):
Speed tables are elongated flat-topped humps, typically 6-10 meters in length, with ramp gradients of 1:10 to 1:15. The extended flat section allows the entire wheelbase of a vehicle to be elevated simultaneously.

Technical specifications: Height typically matches speed humps (75-100mm), but the gentler approach gradients and extended flat section create less discomfort for passengers and less noise/vibration for adjacent residents.

Applications: Speed tables are ideal for:

  • Pedestrian crossing points (raised crossings)
  • Junction treatments (raised junctions)
  • Bus routes where speed reduction is needed with minimal passenger discomfort
  • Areas where noise concerns preclude standard humps

Advantages: Speed tables provide excellent pedestrian priority at crossing points by raising pedestrians to carriageway level and creating a clear visual and tactile signal to drivers. They generate less noise than speed humps and are more comfortable for cyclists.

Raised Pedestrian Crossings:
These are speed tables specifically designed and marked as pedestrian crossing facilities. They combine the speed reduction benefits of vertical deflection with enhanced pedestrian priority and visibility.

Technical specifications: Typically constructed to the same dimensions as speed tables, with the addition of:

  • Zebra crossing markings (Belisha beacons and zig-zag markings) or parallel line markings
  • Tactile paving for visually impaired users
  • Contrasting surface materials to enhance visibility

Applications: Raised crossings are particularly effective near schools, in shopping areas, and at locations with high pedestrian demand. Research shows they reduce vehicle speeds by 8-12 mph and increase driver yielding rates from approximately 10% (at uncontrolled crossings) to 60-80%.

Rumble Strips:
Rumble strips are a distinct category of vertical deflection, using closely-spaced shallow ridges (typically 5-15mm height) to create vibration and noise when traversed, alerting drivers to hazards or speed limit changes.

Technical specifications: Rumble strips may be:

  • Milled: Cut into existing asphalt surface (common on high-speed roads)
  • Rolled: Created during asphalt laying using specialized rollers
  • Applied: Thermoplastic or prefabricated strips bonded to existing surface

Strip spacing typically ranges from 100-400mm, with closer spacing creating more pronounced effect.

Applications: Rumble strips serve different purposes than other vertical deflection measures:

  • Approach warning to hazards (sharp curves, intersections, toll plazas)
  • Transition zones between speed limit areas
  • Edge line rumble strips to prevent run-off-road crashes
  • Center line rumble strips to prevent head-on collisions

Jobling Purser’s Quicksetts rumble strip solutions utilise high-durability thermoplastic materials with reflective elements, providing both tactile and visual warning while maintaining longevity under heavy traffic loads. The precision-engineered profile ensures consistent performance while minimizing noise impact on adjacent properties – a critical consideration often overlooked in rumble strip specification.

Limitations: Rumble strips are less effective at achieving sustained speed reduction than humps or tables. They function primarily as warning devices rather than speed control measures. Noise generation can be problematic near residential properties, requiring careful placement and profile optimization.

Speed Bumps:
Often confused with speed humps, speed bumps are much more aggressive devices—typically 75-100mm high but only 300-600mm in length. This creates a much steeper profile.

Applications: Speed bumps are generally inappropriate for public roads due to their severity. They are used primarily in:

  • Private car parks
  • Industrial sites
  • Locations where speeds must be reduced to walking pace (5 mph or less)

The aggressive nature of speed bumps makes them unsuitable for routes used by emergency vehicles, buses, or cyclists.

Horizontal Deflection Measures: Altering the Path

Horizontal deflection measures use lateral shifts in the vehicle path to reduce speeds and increase driver attention. These measures work by eliminating the straight-line geometry that encourages higher speeds.

Chicanes:
Chicanes create a serpentine path through alternating build-outs on opposite sides of the carriageway. Drivers must slow and steer carefully to navigate the offset path.

Technical specifications: Effective chicanes typically feature:

  • Build-out width: 2.0-3.0 meters into the carriageway
  • Offset distance: 10-20 meters between opposing build-outs
  • Minimum carriageway width at pinch points: 3.5-4.0 meters (to allow two-way traffic with care)

Applications: Chicanes are most effective on straight residential streets where speeding is problematic. They provide additional benefits:

  • Opportunities for street greening (planting in build-out areas)
  • Informal pedestrian crossing points at pinch points
  • Traffic volume reduction (through increased journey complexity)

Limitations: Chicanes require sufficient carriageway width (typically 6+ meters) to implement effectively. They can be problematic for cyclists if poorly designed, and may increase conflicts between opposing traffic flows. Emergency vehicle access must be carefully considered.

Pinch Points (Build-outs, Narrowings):
Pinch points narrow the carriageway at specific locations, typically to a single lane width, requiring drivers to slow and yield to opposing traffic.

Technical specifications:

  • Narrowed width: typically 3.0-3.5 meters
  • Build-out length: 5-10 meters
  • Often combined with priority signage or road markings

Applications: Pinch points work well:

  • At pedestrian crossing locations (providing shorter crossing distance)
  • On approaches to junctions
  • In combination with vertical deflection measures
  • Where traffic volume reduction is a secondary objective

Advantages: Pinch points are relatively inexpensive, provide pedestrian benefits, and can incorporate street greening. They create “self-enforcing” priority through geometry rather than relying solely on signage.

Mini-Roundabouts:
Mini-roundabouts introduce circular geometry at intersections, requiring all traffic to slow and circulate around a central island (which may be fully traversable by large vehicles).

Technical specifications:

  • Inscribed circle diameter: typically 13-28 meters
  • Central island: 1-4 meters diameter (often domed and painted rather than raised)
  • Approach deflection: sufficient to require speed reduction to 15-20 mph

Applications: Mini-roundabouts are effective at:

  • Four-way intersections in residential areas
  • Locations with relatively balanced traffic flows
  • Sites where traditional signal control would be over-engineered

Advantages: Mini-roundabouts reduce severe (right-angle) collisions by 75-85% compared to uncontrolled intersections, according to TRL research. They maintain traffic flow better than signals at low-to-moderate volumes and provide continuous speed reduction rather than stop-start patterns.

Limitations: Mini-roundabouts require adequate space and may be confusing to unfamiliar drivers. They are less suitable for locations with very high pedestrian volumes or significant flow imbalances.

Surface Treatments and Visual Cues: Psychological Speed Reduction

Physical measures are most effective, but visual and tactile treatments can complement them or serve as lower-cost interventions in appropriate contexts.

Textured Pavements:
Textured surfaces use different materials or patterns to create visual and tactile distinction, signaling to drivers that they are entering a different environment requiring different behavior.

Materials:

  • Block paving (clay or concrete pavers)
  • Colored asphalt
  • Exposed aggregate concrete
  • Thermoplastic surface treatments

Applications: Textured pavements are most effective:

  • At transition zones (e.g., entering a village from rural road)
  • In shared space environments
  • At pedestrian crossing points
  • Throughout 20 mph zones to reinforce speed limit

Evidence base: The effectiveness of surface treatments alone is modest—typically 2-4 mph speed reduction. However, when combined with physical measures and as part of comprehensive schemes, they enhance overall effectiveness and create strong visual identity for traffic-calmed areas.

Contrasting Colors and Visual Narrowing:
Painted edge lines, colored surfacing, and other visual treatments can create the perception of a narrower carriageway, encouraging lower speeds.

Applications:

  • Optical narrowing through edge line placement
  • Colored surfacing at pedestrian crossing points
  • Gateway treatments at zone entry points
  • Cycle lane delineation

Limitations: Visual treatments alone produce minimal speed reduction (typically 1-3 mph) and are subject to wear, requiring regular maintenance. They are best used as complementary measures within comprehensive schemes rather than standalone interventions.

Access Management: Controlling Traffic Volume and Composition

Sometimes the most effective traffic calming involves reducing traffic volume rather than merely slowing it.

Modal Filters:
Modal filters use physical barriers (typically planters, bollards, or gates) to prevent through motor traffic while maintaining permeability for pedestrians, cyclists, and sometimes buses.

Types:

  • Full closures: Complete barrier to motor vehicles
  • Bus gates: Enforcement camera allows buses but prohibits general traffic
  • Rising bollards: Automated barriers allowing authorized vehicles
  • Timed closures: Restrictions during specific hours (e.g., school streets)

Applications: Modal filters are highly effective for:

  • Creating low-traffic neighborhoods (LTNs)
  • School streets (closure during drop-off/pick-up times)
  • Preventing rat-running through residential areas
  • Protecting cycling routes

Evidence: Research on London’s low-traffic neighborhoods shows traffic volume reductions of 50-70% on filtered streets, with minimal displacement to boundary roads (typically 10-20% increase, far less than the reduction on internal streets). This represents a net reduction in vehicle kilometers traveled.

Street Closures and Pedestrianization:
Complete closure to motor vehicles transforms streets into pedestrian and cyclist spaces.

Applications:

  • Town center shopping streets
  • Play streets (temporary closures for children’s play)
  • Event spaces
  • Public realm improvements

Considerations: Permanent closures require careful analysis of traffic redistribution, access for deliveries and emergency vehicles, and impacts on adjacent streets. However, the benefits—increased footfall, improved air quality, enhanced public space—can be transformative.

Part 3: The “How” – The Strategic Implementation Framework

Effective traffic calming requires more than selecting appropriate measures from the engineering toolkit. Success depends on systematic process, community engagement, and evidence-based decision-making.

Context is King: The Primacy of Site-Specific Analysis

There is no universal traffic calming solution. A measure that works brilliantly on a residential cul-de-sac may fail catastrophically on a bus route. Effective implementation begins with thorough understanding of context:

Road Classification and Function:

  • Is this a through-route or access-only street?
  • What is the statutory speed limit?
  • Does it carry bus services or serve as an emergency response route?
  • What is the traffic volume and composition?

Physical Constraints:

  • Carriageway width and geometry
  • Drainage and utilities
  • Proximity to residential properties (noise concerns)
  • Topography and gradients

User Needs:

  • Pedestrian volumes and demographics (children, elderly, disabled users)
  • Cyclist volumes and skill levels
  • Parking requirements
  • Access for deliveries and services

Collision History:

  • Collision frequency, severity, and causation factors
  • Vulnerable road user involvement
  • Time-of-day and seasonal patterns

This contextual analysis should draw on multiple data sources: traffic surveys, speed data, collision records, community feedback, and site observations at different times and conditions.

The Five-Step Proven Process

Step 1: Problem Identification and Data Collection

Effective traffic calming addresses specific, evidence-based problems rather than responding to generalized concerns.

Essential data collection:

Speed surveys: Automatic traffic counters should collect 7-day continuous data, providing:

  • Mean speeds
  • 85th percentile speeds (the speed at or below which 85% of vehicles travel—the key metric for engineering analysis)
  • Speed distribution
  • Volume data by time of day

Collision analysis: Review 3-5 years of collision data (STATS19 in UK) to identify:

  • Collision frequency and severity
  • Predominant collision types
  • Vulnerable road user involvement
  • Contributing factors

Community input: Structured consultation to understand:

  • Perceived safety concerns
  • Observed driver behaviors
  • Barriers to walking and cycling
  • Specific locations of concern

Observational studies: Site visits to document:

  • Driver behavior at key locations
  • Pedestrian crossing patterns (including informal crossing points)
  • Cyclist behavior and route choice
  • Conflict points and near-misses

This data collection establishes the baseline against which success will be measured and ensures interventions address actual rather than perceived problems.

Step 2: Goal Setting and Success Criteria

Clear, measurable objectives are essential for scheme design and post-implementation evaluation.

Example objectives:

  • Reduce 85th percentile speeds to 24 mph or below (appropriate for 20 mph zone)
  • Achieve 40% reduction in vehicle volumes on residential streets
  • Reduce KSI collisions by 50% over 3 years
  • Increase walking trips to school by 25%
  • Achieve 80% resident satisfaction with scheme

These objectives should be SMART (Specific, Measurable, Achievable, Relevant, Time-bound) and aligned with broader policy goals such as Vision Zero commitments, air quality objectives, and climate targets.

Step 3: Design and Specification

With clear objectives and robust data, engineers can select and design appropriate measures.

Design principles:

Self-explaining roads: The physical environment should communicate appropriate speeds and behaviors intuitively, without relying solely on signage. A well-designed traffic-calmed street feels different—narrower, more complex, more human-scaled—prompting drivers to slow naturally.

Consistency: Measures should be applied consistently throughout a zone or route. Isolated interventions are less effective than comprehensive schemes that create a consistent low-speed environment.

Redundancy: Multiple measures working together are more effective than single interventions. For example, a 20 mph zone might combine:

  • Gateway treatments at entry points
  • Speed humps at 60-80 meter spacing
  • Textured surfacing throughout
  • Pinch points at pedestrian crossing locations
  • Street trees and greening

Compliance with standards: All designs must comply with relevant standards and guidance:

  • Department for Transport Local Transport Notes (particularly LTN 1/20 for cycle infrastructure)
  • Traffic Signs Regulations and General Directions (TSRGD)
  • Manual for Streets and Manual for Streets 2
  • Equality Act 2010 requirements for accessibility

Technical specifications:

Detailed specifications should address:

  • Precise dimensions and tolerances
  • Materials and construction methods
  • Drainage provisions
  • Signing and lining requirements
  • Lighting considerations
  • Maintenance access

For vertical deflection measures, Jobling Purser’s Quicksetts system offers significant advantages in the specification phase. The modular design allows precise customization to site-specific requirements, with height adjustments achievable in 10mm increments. The rapid installation minimizes traffic management costs and disruption—a critical consideration for schemes on busy routes or in areas where extended road closures are problematic. The high-grade materials ensure longevity, with expected service life exceeding 20 years under normal traffic loads, reducing whole-life costs compared to asphalt alternatives requiring periodic resurfacing.

Step 4: Community Engagement and Consultation

Traffic calming schemes affect daily life for residents, businesses, and road users. Meaningful engagement is both ethically necessary and practically beneficial—schemes with community support are more likely to succeed and less likely to face opposition requiring costly modifications.

Engagement principles:

Early involvement: Engage before designs are finalized, when community input can genuinely influence outcomes.

Transparency: Clearly communicate objectives, constraints, trade-offs, and decision-making processes.

Accessibility: Use multiple engagement methods to reach diverse stakeholders:

  • Public exhibitions and drop-in sessions
  • Online surveys and interactive mapping
  • Targeted outreach to schools, elderly groups, disability organizations
  • Social media and digital platforms
  • Written materials in accessible formats and multiple languages

Evidence-based dialogue: Present data on speeds, collisions, and best practice to inform discussion. Address concerns with evidence rather than dismissing them.

Common concerns and responses:

“Speed humps damage vehicles and cause noise”
Response: Modern designs (particularly sinusoidal profiles and speed tables) minimize discomfort and noise when traversed at appropriate speeds. Noise concerns can be addressed through careful placement away from bedroom windows and use of noise-reducing materials. Vehicle damage occurs only when drivers exceed appropriate speeds—the measures are working as intended.

“Emergency vehicles will be delayed”
Response: Emergency services are consulted during design. Speed cushions, speed tables with gentle gradients, and appropriate spacing allow emergency vehicles to maintain reasonable progress. Research shows that well-designed schemes cause minimal delay (typically 5-10 seconds per measure), while the collision reduction benefits far outweigh this minor impact. Many fire services actively support traffic calming in residential areas.

“Traffic will be displaced to other streets”
Response: Comprehensive schemes treat entire neighborhoods rather than single streets, preventing displacement. Monitoring data from hundreds of schemes shows minimal displacement when area-wide approaches are used. Some traffic “evaporation” typically occurs as drivers choose different routes or modes.

“Businesses will lose customers”
Response: Evidence consistently shows the opposite. Pedestrian-friendly streets with traffic calming generate higher retail revenues. Customers who walk or cycle visit more frequently and spend more over time than those who drive.

Step 5: Installation and Monitoring

Installation best practices:

Phasing: For large schemes, phased implementation allows learning and adjustment. It also spreads costs and minimizes disruption.

Traffic management: Minimize disruption through:

  • Off-peak working where possible
  • Clear advance notification to residents and businesses
  • Efficient construction methods (Quicksetts installation typically requires only 2-4 hours per hump vs. 1-2 days for asphalt)
  • Coordination with other street works

Quality assurance: Rigorous inspection ensures compliance with specifications and standards. Defects should be remedied before handover.

Post-implementation monitoring:

Monitoring is essential to:

  • Verify that objectives have been achieved
  • Identify any unintended consequences
  • Build evidence base for future schemes
  • Demonstrate value for money to decision-makers

Monitoring should include:

Speed surveys: Repeat baseline surveys at 3-6 months and 12 months post-implementation to measure speed reduction.

Collision monitoring: Track collision data for 3-5 years post-implementation (recognizing that collision frequency is subject to random variation, requiring longer monitoring periods for statistical significance).

Volume monitoring: Measure traffic volumes on treated streets and adjacent routes to assess displacement effects.

User surveys: Assess resident satisfaction, perceived safety, and behavior change (walking/cycling uptake).

Observational studies: Document changes in pedestrian crossing behavior, cyclist route choice, and driver compliance.

Case Study: Comprehensive Traffic Calming in Waltham Forest, London

Waltham Forest’s “Mini-Holland” program, implemented 2015-2020, provides compelling evidence of traffic calming effectiveness at scale.

Context: The program created low-traffic neighborhoods across multiple areas, using modal filters, speed humps, raised crossings, and public realm improvements.

Measures implemented:

  • 73 modal filters preventing through motor traffic
  • 127 speed humps and tables
  • 42 raised pedestrian crossings
  • Extensive cycle infrastructure
  • Street greening and public space improvements

Results (measured 2020):

  • Speed reduction: 85th percentile speeds reduced from 28-32 mph to 20-23 mph on treated streets
  • Volume reduction: 56% reduction in motor traffic on filtered streets
  • Minimal displacement: 3-8% increase on boundary roads (far less than reduction on internal streets)
  • Collision reduction: 47% reduction in KSI casualties in treated areas vs. 28% reduction borough-wide
  • Mode shift: Cycling increased 89% in treated areas vs. 19% borough-wide; walking increased 12%
  • Air quality: NO₂ concentrations reduced by 9% on treated streets
  • Public support: 58% of residents supported schemes, 23% opposed (remainder neutral)
  • Economic impact: Retail footfall increased 7% in treated areas vs. 2% decline in comparison areas

Cost-benefit analysis: With implementation costs of approximately £27 million and estimated benefits (collision reduction, health improvements, air quality) of £89 million over 30 years, the benefit-cost ratio exceeds 3:1.

This case study demonstrates that comprehensive, area-wide traffic calming delivers measurable benefits across multiple domains while maintaining public support.

Overcoming Common Objections: Evidence-Based Responses

Emergency Vehicle Access

Objection: “Traffic calming will delay ambulances and fire engines, costing lives.”

Evidence-based response:
Emergency services are statutory consultees for traffic calming schemes, ensuring their operational needs are considered. Research by the UK Fire and Rescue Service shows:

  • Well-designed speed cushions cause minimal delay (average 2-3 seconds per cushion)
  • Speed tables with 1:15 gradients can be traversed at 20-25 mph without significant discomfort
  • The collision reduction benefits of traffic calming far exceed any minor delays—preventing collisions reduces emergency call-outs

A study in Portland, Oregon found that traffic calming reduced emergency response times in treated neighborhoods by 14% overall, because the reduction in collision-related call-outs more than offset any minor delays caused by physical measures.

Modern design guidance (including DfT standards) requires emergency vehicle access to be maintained. Where concerns exist, speed cushions or tables with gentle gradients should be specified rather than aggressive humps.

Noise and Vibration

Objection: “Speed humps create noise and vibration, disturbing residents.”

Evidence-based response:
Noise generation depends on hump profile and driver behavior. Research by TRL shows:

  • Sinusoidal profile humps generate 2-3 dB(A) less noise than older circular profiles
  • Speed tables generate less noise than humps due to gentler gradients
  • Noise occurs primarily when drivers brake harshly before humps or accelerate aggressively after—behavior that diminishes as drivers adapt
  • Overall noise levels typically decrease in traffic-calmed areas due to lower speeds and reduced traffic volumes

Careful placement (avoiding locations directly outside bedroom windows where possible) and specification of modern profiles minimizes noise concerns. The noise reduction from lower overall speeds typically outweighs any localized noise at hump locations.

For particularly sensitive locations, alternative measures (chicanes, pinch points, or speed tables) should be considered.

Traffic Displacement

Objection: “Traffic calming just pushes problems onto other streets.”

Evidence-based response:
Displacement is a legitimate concern for single-street schemes but is largely avoided through area-wide approaches. Research consistently shows:

  • Comprehensive schemes treating entire neighborhoods show minimal displacement (typically 10-20% of the volume reduction appears on boundary roads)
  • Some traffic “evaporates”—drivers choose different destinations, travel at different times, or switch modes
  • Boundary roads often already carry higher volumes and are more appropriate for through-traffic
  • Monitoring of hundreds of schemes shows net reduction in vehicle kilometers traveled

The solution is to implement traffic calming comprehensively rather than piecemeal, treating entire neighborhoods or corridors rather than isolated streets.

Part 4: The Future and Your Role

The Future of Traffic Calming: Innovation and Integration

Traffic calming is evolving rapidly, driven by technological innovation, changing mobility patterns, and increasingly ambitious policy objectives.

Adaptive and Intelligent Measures:
The next generation of traffic calming will be responsive and data-driven. Emerging technologies include:

  • Variable speed humps: Actuated systems that rise during school hours or high pedestrian periods and retract at other times, optimizing for different conditions
  • Smart speed limit signs: Dynamic displays that adjust limits based on real-time conditions (weather, pedestrian activity, time of day)
  • Sensor-integrated measures: Speed humps with embedded sensors providing continuous monitoring data, enabling evidence-based optimization

IoT Integration and Data Analytics:
The Internet of Things enables unprecedented insight into street performance:

  • Real-time speed and volume monitoring
  • Pedestrian and cyclist counting
  • Air quality and noise monitoring
  • Predictive analytics identifying emerging safety concerns before collisions occur

This data infrastructure supports adaptive management, allowing authorities to optimize interventions continuously rather than relying on periodic reviews.

Autonomous Vehicles:
Self-driving vehicles will transform traffic calming requirements. Autonomous vehicles can be programmed to respect speed limits perfectly, potentially reducing the need for physical measures. However:

  • Mixed traffic environments (autonomous and human-driven vehicles) will persist for decades
  • Physical measures provide benefits beyond speed control (pedestrian priority, public realm quality)
  • Autonomous vehicles may enable more sophisticated traffic calming (dynamic routing to avoid residential streets, platooning to reduce volumes)

The transition period will require flexible infrastructure that accommodates both traditional and autonomous vehicles.

Climate-Responsive Design:
Future traffic calming will integrate climate adaptation and mitigation:

  • Permeable paving in build-outs for sustainable drainage
  • Street trees and green infrastructure for cooling and carbon sequestration
  • Solar-powered lighting and signage
  • Materials with low embodied carbon

Equity and Inclusion:
Increasingly, traffic calming is recognized as an equity issue. Low-income communities and communities of color often experience higher traffic volumes, speeds, and collision rates. Future practice will prioritize:

  • Equitable distribution of traffic calming investment
  • Community-led design processes
  • Accessibility for disabled users
  • Addressing historic underinvestment in disadvantaged areas

Jobling Purser: Your Partner in Creating Safer Streets

For over three decades, Jobling Purser has been at the forefront of traffic calming innovation, providing local authorities, contractors, and consultants with engineered solutions that deliver measurable results.

Why Jobling Purser?

Engineering Excellence: Our products are designed by engineers for engineers. Every specification is optimized for performance, durability, and compliance with UK standards. Our technical team provides expert support throughout the specification, procurement, and installation process.

Quicksetts Technology: Our flagship Quicksetts modular speed hump system represents a quantum leap in traffic calming infrastructure:

  • Rapid installation: 2-4 hours per hump vs. 1-2 days for asphalt, minimizing disruption and traffic management costs
  • Exceptional durability: High-grade materials engineered for 20+ year service life
  • Flexibility: Modular design allows height adjustment, future modification, and simplified maintenance
  • Sustainability: Reduced installation time means lower carbon emissions; long service life reduces whole-life environmental impact

Comprehensive Product Range: Beyond Quicksetts, we offer:

  • Traditional and sinusoidal profile speed humps in multiple materials
  • Speed cushions optimized for bus routes
  • Rumble strips with precision-engineered profiles for effective warning with minimized noise
  • Pedestrian crossing systems
  • Bollards and street furniture
  • Custom solutions for unique site requirements

Evidence-Based Approach: We don’t just sell products—we partner with you to achieve outcomes. Our technical team can assist with:

  • Site assessment and measure selection
  • Scheme design and optimization
  • Compliance verification
  • Post-implementation monitoring and evaluation

Proven Track Record: Our products have been specified in thousands of successful schemes across the UK and internationally. We work with leading local authorities, consulting engineers, and contractors who demand the highest standards.

Commitment to Innovation: We continuously invest in research and development, ensuring our products incorporate the latest materials science, manufacturing technology, and design thinking. We’re not satisfied with “good enough” – we’re committed to excellence.

Your Next Steps: From Insight to Action

Whether you’re a transport engineer developing a comprehensive neighborhood scheme, a local authority decision-maker allocating capital budgets, or a community advocate pushing for safer streets, the evidence is clear: traffic calming works.

The question is not whether to implement traffic calming, but how to do so effectively, efficiently, and equitably.

For Engineers and Consultants:

  • Conduct rigorous site assessment using the framework outlined in this guide
  • Specify measures matched to context, drawing on the taxonomy of interventions
  • Engage communities meaningfully throughout the process
  • Monitor and evaluate rigorously to build the evidence base

For Local Authority Decision-Makers:

  • Adopt area-wide approaches rather than piecemeal interventions
  • Allocate sufficient resources for comprehensive schemes that deliver transformative results
  • Prioritize equity in investment allocation
  • Commit to Vision Zero and use traffic calming as the primary engineering tool for achieving it

For Community Advocates:

  • Build coalitions around evidence-based proposals
  • Engage constructively with technical professionals
  • Demand comprehensive schemes that address root causes rather than symptoms
  • Hold authorities accountable for delivering safe streets for all users

Contact Jobling Purser:
Our technical team is ready to support your next project. Whether you need specification advice, product information, or partnership on a complex scheme, we’re here to help.

Visit our website to explore our full product range, download technical specifications, and access case studies demonstrating real-world performance. Request a consultation to discuss your specific requirements and discover how our solutions can help you create safer, more livable streets.

Together, we can transform our streets from vehicle throughways into community assets—places where children play safely, where elderly residents cross without fear, where businesses thrive, and where the air is clean. The engineering toolkit exists. The evidence base is robust. The time for action is now.

Traffic calming is not just about slowing cars – it’s about reclaiming our streets for people. Let’s build that future together.