Most homeowners don't expect to need a traffic consultant for their extension project. But London's congested streets and strict parking controls mean councils increasingly require professional transport input, especially for larger projects or properties in controlled parking zones.
We've evaluated London's traffic consultants based on residential project experience, council approval rates, understanding of domestic extension requirements, and value for money. This guide focuses on consultants who handle home extensions rather than commercial developments.
When Do You Need a Traffic Consultant?
Common Triggers for Transport Assessments
Basement Extension
Construction traffic management often required
Property in CPZ
Parking impact assessment may be needed
Near Red Route (TfL Road)
TfL consultation required
New or Altered Vehicle Access
Crossover design and visibility splays
Conversion to Multiple Units
Parking provision calculations needed
Loss of Parking Spaces
Justification for parking reduction
Planning Condition
Council requiring CMP pre-commencement
Narrow Street Access
Swept path analysis for construction vehicles
Even when not specifically required, having a transport consultant can strengthen your application in areas where parking and traffic are contentious issues with neighbours or councillors.
Typical Traffic Consultant Costs
| Service | Price Range | Turnaround |
|---|---|---|
| Parking Survey | £300 - £600 | 5 - 10 days |
| Transport Statement | £500 - £1,200 | 7 - 14 days |
| Construction Management Plan | £400 - £900 | 5 - 10 days |
| Vehicle Crossover Design | £350 - £700 | 5 - 7 days |
| Swept Path Analysis | £250 - £500 | 3 - 5 days |
| Full Residential Package* | £800 - £1,800 | 10 - 21 days |
*Full package typically includes parking survey, transport statement, and construction management plan
Top 10 Traffic Consultants for London Extensions
Caneparo Associates
Leading residential transport specialists in London
Starting Price
£450 (transport statement)
Council Approval Rate
97%
Response Time
24-48 hours
Best for: Premium residential projects in Central and West London. Excellent relationships with Westminster, Kensington & Chelsea, and Camden highways teams. Known for getting difficult applications through.
i-Transport
National consultancy with strong London residential division
Starting Price
£550 (transport statement)
Coverage
All London boroughs
Response Time
2-3 days
Best for: Complex projects requiring robust technical justification. Strong at dealing with TfL consultations and projects near major road networks. Comprehensive reports that stand up to scrutiny.
Ardent Consulting Engineers
Specialist residential and small development consultants
Starting Price
£395 (transport note)
Specialisation
Residential projects
Response Time
48-72 hours
Best for: Cost-effective solutions for standard residential applications. Good understanding of what councils actually need versus over-engineering. Quick turnaround for Construction Management Plans.
RGP Transport Planning
Boutique firm focused on residential schemes
Starting Price
£425 (parking survey + statement)
Experience
15+ years residential
Response Time
3-5 days
Best for: Homeowners wanting personalised service and direct contact with the consultant handling their project. Particularly good at parking surveys in Controlled Parking Zones. Strong South London coverage.
TTP Consulting
Full-service transport planning consultancy
Starting Price
£600 (transport statement)
TfL Experience
Extensive
Response Time
3-5 days
Best for: Projects near TfL red routes or major junctions requiring formal TfL consultation. Expert at navigating the TfL approval process and understanding their specific requirements. Higher price but worth it for complex cases.
Connect Consultants
Basement extension specialists
Starting Price
£350 (CMP only)
Specialisation
Basement CMPs
Response Time
24-48 hours
Best for: Basement extensions requiring Construction Management Plans. Deep expertise in skip logistics, spoil removal scheduling, and coordinating with basement contractors. Fast turnaround for condition discharge.
Paul Basham Associates
Established firm with London residential team
Starting Price
£500 (transport statement)
Track Record
25+ years
Response Time
3-5 days
Best for: Projects that might face appeal or objections requiring robust professional evidence. Reports are comprehensive and designed to withstand scrutiny. Good for contentious applications.
David Tucker Associates
Multi-disciplinary with strong highways expertise
Starting Price
£450 (transport note)
Services
Transport + highways
Response Time
5-7 days
Best for: Projects requiring both transport planning and highways engineering input. Excellent for vehicle crossover design and visibility splay calculations. Can coordinate Section 278 agreements if needed.
Motion
Sustainable transport specialists
Starting Price
£550 (transport statement)
Focus
Low-car developments
Response Time
5-7 days
Best for: Projects proposing reduced or no parking provision. Expert at arguing sustainable transport credentials and making the case for car-free or low-car developments. Strong in inner London boroughs.
Highway Matters
Budget-friendly option for simpler requirements
Starting Price
£295 (basic CMP)
Best For
Standard CMPs
Response Time
48-72 hours
Best for: Straightforward Construction Management Plans for standard extensions. Good value for money when requirements are clear-cut. May need to escalate to larger firms for complex transport statements.
Understanding Construction Management Plans
Construction Management Plans (CMPs) are increasingly required by London councils, particularly for basement extensions and projects in areas with parking restrictions. They detail how construction traffic and activities will be managed to minimise disruption to neighbours and the highway network.
Typical CMP Contents
Delivery Schedule
When and how materials will be delivered, vehicle sizes, frequency
Spoil Removal (Basements)
Skip storage, lorry movements, estimated number of loads
Worker Parking
Where site workers will park, whether permits needed
Traffic Routes
Approved routes for construction vehicles
Working Hours
Confirmation of compliance with council restrictions
Parking Surveys Explained
Parking surveys demonstrate that on-street parking capacity exists to accommodate any additional demand from your development, or that your proposal won't negatively impact parking availability.
Lambeth Methodology
Many London boroughs use the "Lambeth Methodology" which requires overnight surveys (typically midnight and 5am) to establish baseline parking stress. If stress exceeds 90%, additional justification may be needed for developments adding parking demand.
Survey Area
Surveys typically cover a 200m radius from the site, counting available and occupied parking spaces on all roads within the study area. Some councils may require a wider area for larger developments.
When Required
Usually required for: HMO conversions, flat subdivisions, proposals that remove off-street parking, and developments proposing car-free schemes in areas with high parking stress.
Frequently Asked Questions
Do I need a traffic consultant for a rear extension?
Generally no, unless your extension requires a planning condition for a Construction Management Plan (common for basements), you're in a CPZ and the council raises parking concerns, or the extension results in loss of off-street parking.
What's the difference between a Transport Statement and Transport Assessment?
Transport Statements are lighter documents for smaller schemes with limited transport impact. Transport Assessments are comprehensive studies for major developments. Residential extensions typically only require Statements, if anything.
Can my architect prepare the Construction Management Plan?
Some architects prepare basic CMPs, but councils in stricter boroughs may require documents from qualified transport planners. If your CMP is rejected, you'll need to engage a specialist anyway, potentially causing delays.
What if my project is near a red route?
Properties on or accessing from TfL's Strategic Road Network (red routes) require TfL consultation. Your local council will refer the application to TfL, who have 21 days to respond. A traffic consultant experienced with TfL can smooth this process.
How do parking permits for builders work?
Most boroughs offer contractor parking permits (sometimes called "trade permits") for construction vehicles and worker parking. Your CMP should detail how many permits will be needed and the application process varies by borough.
Planning an Extension in London?
Check your property's planning constraints including CPZ status and nearby red routes with our instant property report.
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