Section 38 adoption agreements for new estate roads
A section 38 agreement under the Highways Act 1980 turns a new estate road into highway maintainable at public expense. Here is what the highway authority checks, what the bond and commuted sums cover, and how adoption fits the build programme.
Section 38 road adoption is the agreement under which a highway authority takes on a new estate road as highway maintainable at public expense. Sign one and the council inherits the carriageway, the footways, the lighting and usually the highway drainage once the road is built to standard and has survived a maintenance period. Skip it and the road stays private, which means every buyer's solicitor asks who pays to resurface it in twenty years.
The agreement sits in section 38 of the Highways Act 1980. It is a different instrument from a section 278 agreement, which covers works you carry out to an existing highway, such as a new bellmouth or a right-turn lane. Most residential schemes of any size need both.
What adoption means to buyers and to your programme
An adopted road is maintained by the highway authority out of public funds. An unadopted road is maintained by whoever the deeds say, which on a modern estate usually means a management company funded by an estate charge on every plot.
Lenders and conveyancers treat the difference as material. Where a road is not adopted and no section 38 agreement is in place, the buyer's solicitor will look for a road bond or an indemnity, and the sale can stall while it is arranged.
There is also a statutory prompt to deal with the question early. The Advance Payments Code in sections 219 to 225 of the Highways Act 1980 requires a payment or security to the street works authority before building work starts on a new street that is not maintainable at public expense. Having a section 38 agreement in place is one of the exemptions, which is why developers usually want the agreement signed before the first plot goes up rather than after.
Adoptable geometry, drainage and lighting
Every highway authority publishes its own design guide, and those guides differ enough that a layout approved in one county will fail in the next. What they share is a common set of subjects:
- Carriageway widths, forward visibility and junction visibility splays, with tracking drawings for a refuse vehicle and a fire appliance.
- Vertical alignment, gradients, longitudinal falls and the position of gullies.
- Footway widths, crossing points, tactile paving and dropped kerbs to the authority's detail.
- Street lighting to the authority's specification, including column type, lantern output and the electrical connection.
- Construction depths, sub-base specification and materials, with any non-standard surfacing treated separately.
- Street naming, signing and lining.
Manual for Streets and Manual for Streets 2 remain the reference points for residential street design in England, and LTN 1/20 governs cycle infrastructure where the scheme includes it. Where the site connects to the strategic road network, National Highways is the relevant authority for the connection itself.
The layout you get permission for and the layout that is adoptable are not automatically the same drawing. That gap is the single most common cause of delay on small estates. Where the scheme is large enough to need a Transport Assessment, the highway authority's comments on the assessment usually flag the adoption issues months before the section 38 drawings are drawn, and they are worth reading as a technical checklist rather than a consultation response.
The agreement, the bond and the maintenance period
The section 38 agreement is a deed between the developer and the highway authority. It records the extent of the works, the approved drawings, the technical approval process, the inspection regime and the securities.
The commercial elements usually run in this order:
- Technical approval of the detailed engineering drawings, paid for by a checking fee calculated on the value of the works.
- A bond or other surety, sized so the authority could complete the road if the developer failed, released in stages as work is certified.
- An inspection fee covering the authority's site supervision through construction.
- A provisional certificate once the road is built and inspected, which starts the maintenance period.
- A maintenance period, commonly twelve months, during which the developer repairs defects and the road carries construction traffic.
- A final certificate and adoption, at which point the highway becomes maintainable at public expense.
Commuted sums are the item developers under-budget most often. Authorities charge them for assets they will maintain but did not ask for, such as structures, non-standard paving, highway trees, or drainage features with a shorter design life than the road. Ask for the commuted sum policy at the pre-application stage, because it is published by most authorities and it changes the appraisal.
Drainage, and who adopts what
Highway drainage that discharges to a public sewer is normally adopted with the road. Sustainable drainage features are where the position gets untidy.
Schedule 3 to the Flood and Water Management Act 2010, which would have created a separate SuDS approving body with an adoption duty, is not in force in England, so adoption still depends on agreement. In practice three routes exist. The highway authority adopts features that sit within the highway and meet its specification. The sewerage undertaker adopts sewers and some SuDS under a section 104 agreement made under the Water Industry Act 1991, subject to its design and construction guidance. Anything else stays private and passes to a management company.
Decide this at the layout stage, not at the section 38 stage. A basin sitting in open space outside the highway boundary, fed by a pipe nobody will adopt, is a management liability created by a drawing. The Drainage Strategy submitted with the planning application should already say who is expected to adopt each element and on what basis, and the lead local flood authority will ask.
Choosing a management company instead
Some developers deliberately keep estate roads private. The reasons are real: adoptable standards can force wider carriageways and more tarmac than the design wants, commuted sums are avoided, and the authority's specification may rule out the surfacing the planning permission approved.
The costs are also real. Buyers pay an estate charge for the life of the property. Standards of maintenance vary with the management company. And the Leasehold and Freehold Reform Act 2024 introduced protections for homeowners paying estate management charges, brought into force in stages, so the regulatory position on private estates is moving rather than settled. Check where it stands before you build the model.
A middle position is common on small schemes: adopt the through route and the footway connections, keep the shared surface courtyards and the private drives out of the agreement, and be honest in the sales pack about which is which.
Sequencing adoption against the build programme
Start the technical approval submission while the reserved matters or discharge of conditions work is still running. Technical approval is an engineering review, not a planning one, and it routinely takes longer than developers allow because comments come back in rounds.
Build the base course early and leave the surface course until the plots are finished, because construction traffic will damage a new wearing surface. Agree that sequence with the authority in the agreement rather than assuming it. Then programme the maintenance period against your last completions, since the final certificate cannot come before the period has run and the defects are closed.
One more practical point. Construction traffic on a partly built estate road is a planning matter as well as an engineering one, and the Construction Traffic Management Plan approved under condition should match the phasing in the section 38 agreement. Where the two disagree, the site foreman follows whichever arrived last, and neither authority is impressed.
If you are scoping the transport evidence for an application that will end in an adoption agreement, enter the site postcode on PlanScope to see which highway and drainage documents the scheme is likely to need, starting with a Transport Statement for smaller schemes.
This is general guidance and not legal advice. Check the position with your highway authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
What is the difference between a section 38 and a section 278 agreement?
Section 38 of the Highways Act 1980 covers the adoption of a new street built by a developer, so the authority takes on future maintenance. Section 278 covers works the developer carries out to an existing public highway, such as a new junction or footway crossing. Most residential schemes of any size need both agreements.
How long is the maintenance period before a road is adopted?
Twelve months from the provisional certificate is the common position, though authorities set their own terms in the agreement. During that period the developer repairs defects and the road carries construction traffic. Adoption follows the final certificate, once outstanding defects are closed and any commuted sums have been paid.
Does the highway authority adopt sustainable drainage features?
Only where they sit within the highway and meet its specification. Schedule 3 to the Flood and Water Management Act 2010 is not in force in England, so there is no general adoption duty. Sewers and some features can be adopted by the sewerage undertaker under a section 104 agreement, and the rest stays private.
What is the Advance Payments Code?
Sections 219 to 225 of the Highways Act 1980 require a payment or security to the street works authority before building starts on a new street that is not maintainable at public expense. Having a section 38 agreement in place is one of the exemptions, which is why developers usually sign before the first plot is built.
What are commuted sums for on road adoption?
They cover future maintenance of assets the authority will inherit but would not normally build, such as structures, non-standard paving, highway trees or drainage features with a shorter design life than the carriageway. Most authorities publish a commuted sums policy, so ask for it at pre-application stage and put it in the appraisal.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.