Transport contributions and the tests obligations must meet

A transport contribution can only be a reason for granting permission if it passes three statutory tests: necessary to make the development acceptable in planning terms, directly related to the development, and fairly and reasonably related in scale and kind to it. That is regulation 122 of the Community Infrastructure Levy Regulations 2010, and it applies to every obligation regardless of what an adopted supplementary document says the tariff is.

Authorities ask for sums that fail those tests more often than practitioners challenge them. The reason is usually programme pressure rather than the merits.

The statutory tests an obligation must satisfy

The three limbs do different work and it helps to keep them apart.

Necessary means the development would be unacceptable without the obligation. If the scheme is acceptable anyway, the contribution is not necessary and cannot lawfully be a reason for granting permission, however desirable the spending would be.

Directly related means there has to be a real connection between the development and what the money is spent on. A payment towards a scheme on the other side of the district, which residents of the development will never use, fails.

Fairly and reasonably related in scale and kind means proportionality. A development generating two per cent of the traffic through a junction should contribute towards two per cent of the improvement, not all of it and not a round number picked for convenience.

Those tests are echoed in national policy and they were applied by the Supreme Court in the context of pooled contributions, where an obligation with no more than a general connection to the development was held incapable of being a reason for granting permission. The principle since then is that a tariff has to be traceable to an identified impact of the particular scheme.

Applying them to bus, cycle and crossing contributions

Different transport asks fare differently against the tests.

Bus contributions are the most commonly contested. Pump-priming a route for a fixed period while a development builds out and occupancy rises can be justified. Perpetual revenue support usually cannot, because it fails the necessity test once the service is commercially viable or once the alternative is that the service would have been withdrawn anyway.

Crossings and cycle links are the easiest to justify and the easiest to get wrong. Tie them to a desire line demonstrated in the Transport Assessment, and the argument is short.

Evidence the authority needs to justify a request

Ask for it, politely, in writing. A properly evidenced request has four components and a weak one has none of them.

The identified impact, drawn from the transport evidence rather than asserted. The scheme the money will fund, identified with a cost estimate and a programme. The apportionment method, showing how your share was calculated. And the policy basis, meaning an adopted development plan policy or a supplementary document supported by evidence.

Where a council relies on a per-dwelling tariff from a supplementary planning document, the document itself has to rest on evidence connecting the tariff to identified infrastructure need. A tariff invented for administrative convenience does not survive scrutiny at appeal.

Infrastructure funding statements, published annually by charging and receiving authorities, are a useful source. They show what has been collected, what has been spent and what remains unspent, and an authority asking for a contribution towards a scheme it has already funded has a problem.

Calculating a proportionate sum

Two methods dominate and both are defensible when applied honestly.

The impact share method takes the development's trips as a proportion of total flows through the affected infrastructure and applies that percentage to the scheme cost. It suits junction improvements and crossings. Show the trip generation source, the assignment and the arithmetic.

The tariff method applies a published per-dwelling or per-square-metre figure derived from an evidenced infrastructure plan. It suits sustainable transport packages spread across many schemes. Check that the tariff has been tested and that it is being applied as published rather than adjusted upwards.

Trip generation underpins both. Where the rates come from the national trip rate database, state the site categories, the filters and the date of extraction so the assumptions can be checked, and cross-refer the equivalent analysis in our note on trip generation for student and age-restricted housing where the standard categories do not fit.

Parking provision interacts with all of it. A scheme with provision below standard usually attracts a larger sustainable transport ask, and the evidence for that position is set out in our guide to evidencing parking provision above or below standard.

An illustrative example

A 60-dwelling scheme where the authority seeks £180,000 towards a junction improvement costing £900,000. The transport assessment shows the development contributing 6 per cent of peak hour flows through the junction, which supports a proportionate sum of £54,000. The applicant offers that figure with the calculation shown, together with a cycle link contribution tied to a named route running from the site frontage to the secondary school, and declines the remainder on scale and kind grounds. The authority accepts the revised package. This example is illustrative rather than drawn from a specific case.

Interaction with the levy and double charging

Where a charging schedule is in place, the levy funds the infrastructure listed as levy-funded and section 106 handles site-specific mitigation. Seeking a contribution through an obligation for infrastructure that the levy is funding is double charging, and it fails the necessity test.

The restriction on pooling more than five obligations towards a single item was removed in 2019, so the old argument that a sixth contribution is unlawful no longer runs. That has not made pooled tariffs easier to justify, because the statutory tests and the Supreme Court's approach still require a real connection between the development and the spending.

Check the authority's charging schedule and its infrastructure list before you concede anything. Where the junction you are being asked to fund appears on the levy list, say so.

Trigger points, indexation and clawback

The drafting is where money is won and lost after the principle is settled.

Push payment triggers as late as the authority will accept. Occupation of a stated number of units is better than start on site, and a phased payment tied to occupancy is better still on a scheme that builds out over years.

Expect indexation and negotiate the index. A construction cost index is appropriate for a contribution towards physical works, and a general inflation measure for revenue support. Fix the base date at the date of the agreement rather than at some earlier point.

Insist on clawback. An obligation to return the contribution, with interest, where it has not been spent or committed within a stated period is standard drafting and authorities rarely resist it. Five or ten years are the usual periods.

And define the purpose tightly. A contribution described as "towards sustainable transport measures in the vicinity" is impossible to police, whereas one tied to a named scheme can be tracked in the infrastructure funding statement.

Challenging a request that fails the tests

Do it early, in correspondence, with reasons. Set out which limb of regulation 122 you say the request fails and why, and offer the sum you consider proportionate with the calculation attached.

Most requests are resolved at that stage because officers have limited appetite for defending an unevidenced figure. Where agreement is impossible, the options are to enter the agreement under protest and accept the cost, or to decline and take the refusal to appeal, where inspectors regularly decline to give weight to obligations failing the tests.

Weigh the cost of the appeal against the contribution. On a small scheme a disputed £20,000 rarely justifies six months of delay. On a larger one, an unevidenced tariff applied across a whole scheme frequently does.

Set the whole argument out in the Travel Plan and the transport evidence rather than leaving it to the legal drafting stage, because an obligation is far easier to resist before the heads of terms are agreed than after.

This is general guidance, not legal advice. Check the position with your local planning 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.