Safer Cycling and Walking to and from North West Cambridge  

The problem:

Drivers rat-run down Thornton Road in order to selfishly queue-jump past the vehicles waiting on Girton Road and Huntingdon Road.
These rat-running vehicles often make it impossible to cycle along Thornton Road.
Rat-runners render Thornton Road impassable to cycles The queue of rat-runners often extends past the Thornton Road/Thornton Way junction
For further information about the rat-run problem, see the youtube video: EddingtonSafety Part 5 [4 mins].

Proposal for eliminating rat-running on Thornton Road

We suggest that morning peak-hour rat-running could be eliminated by introducing a "timed closure" that, during morning peak hours (eg 7am-10am) Monday to Friday, makes part of Thornton Road one-way (northbound). During those hours, southbound travel by motor vehicles through that part of Thornton Road would be forbidden by a no-entry sign.

At all other times, Thornton Road would be two-way, and, at the new constriction, northbound motor traffic would have priority over southbound motor traffic. The rule in force would be indicated by "Variable signs" as shown in table 1 below.

At all times, cycling would be permitted in both directions, and dedicated cycle lanes would be included at the new constriction.

We also propose that Thornton Road, Thornton Close, and Thornton Way be designated a "Home Zone". (See Table 2 below.)

Figure 1: Diagram of proposed islands (blue) and road markings (cyan, red), assuming a road of width 6.2m. Each island would have a "variable sign" on it, like the ones shown in Figure 3 below; the signs would display the signs shown in Table 1 below.
[Click image to view and zoom in.]

variable sign A time shown variable sign B
one way 7am-10am
(morning peak)
no entry
you have priority 10am-7am
(all times apart from the morning peak)
you have not got priority
Table 1: what the variable signs would show in the two directions. Sign A faces northbound traffic; Sign B faces southbound traffic.

click to view image and then zoom in
Figure 2: Three possible locations (options L, M, N) for the new constriction and cycle lanes. [Click image to view and zoom in.]
Option L has the advantage that it is located in a part of Thornton Road with no driveways and no need for on-street parking.
Option M has the advantage that there would be a clear view of the new constriction for traffic coming from either direction.
Option N has the advantage of using the existing junction of Thornton Road and Thornton Way as a natural location for a traffic calming feature.
Satellite images courtesy of Google.

Precedents for the features shown:

  • The "variable signs" and "timed closure" are based on Grafton Road in London, which has had timed closures (at peak times) to eliminate rat-running for many years, and which had variable signs installed a couple of years ago.
    The Google-Streetview images in figure 3 (below) illustrate the road signs in the neighbourhood of this timed closure point, and the closure point itself; figure 3 also includes an excerpt from Camden's latest consultation which redesigned the timed closure and added the variable signs.
  • The dimensions of the cycle lanes and islands are based on the cycle lanes and islands outside Selwyn College on Grange Road; in fact the cycle lane widths proposed are actually a little wider than those on Grange Road.
  • The width of the constriction is similar to the width of the constrictions on Storey's Way and Windsor Road, but the harsh metal posts that are found on Storey's Way and Windsor Road are not proposed here.
  • The distances from the islands to the "Give Way" road markings are based on the road markings outside Robinson College on Grange Road.

Figure 3: Grafton Road, London
view from North
view from South

Table 2:

Examples of Signs indicating Speed limits / Home Zone / no through route

Girton Road / Huntingdon Road Junction, viewed from the Bunker's Hill side of Huntingdon Road, looking up Girton Road - These are the morning-peak queues that the rat-runners are attempting to queue-jump.
This webpage is maintained by Prof David MacKay.