Technical Note

Project:SpeedLimitReviewBirminghamCityTo:David Clayfield

Subject:A4040Route StudyFrom: Chris Young

Date:15thDecember 2010cc:File

  1. A4040 Route Study Summary

1.1Location

The A4040 Route for the purposes of this Speed Limit Review comprises of the lengths of A4040 Highfield Road, A4040 Fox Hollies Road, and A4040 Stockfield Road. In addition the route study was expanded to cover the 40mph restrictions along the non A Class routes of Robin Hood Lane and Highfield Road.

Section Link / Length (Km) / Speed Limit / Collisions / No. of Speed Related Collisions
A4040 Fox Hollies Road / 2.5 / 40 / 39 / 12
A4040 Highfield Road / 0.6 / 40 / 7 / 3
A4040 Stockfield Road / 1.3 / 40 / 51 / 11
Highfield Road / 0.5 / 40 / 1 / 1
Robin Hood Lane / 0.8 / 40 / 7 / 2

1.2Accident Analysis

The 3 year recorded injury accident history (01/09/2007 to 31/08/2010) has shown a total of 105 collisions recorded for the routeswithin the A4040 study.

Section Link / Length (Km) / Total Accidents / Total KSIs / Collisions per Km / Speed Related Collisions / Speed Related Collisions* %
A4040 Fox Hollies Road / 2.5 / 39 / 6 / 15.6 / 12 / 31%
A4040 Highfield Road / 0.6 / 7 / 1 / 11.7 / 3 / 43%
A4040 Stockfield Road / 1.3 / 51 / 4 / 39.2 / 11 / 22%
Highfield Road / 0.5 / 1 / 0 / 2.0 / 1 / 100%
Robin Hood Lane / 0.8 / 7 / 1 / 8.8 / 2 / 29%

On reviewing the recorded personal injury accident data held for the above road lengths, a dominant accident trend was collisions involving vulnerable road users, with particular emphasis to collisions located along A4040 Fox Hollies Road. It was noted a sizeable proportion of the collisions recorded related to pedestrians crossing at the controlled Zebra crossing facilities, whereby drivers were failing to give way to pedestrians.

For reference the current guidance LTN1/95 states Zebra crossings should not be installed on roads with an 85%ile speed of 35mph or above.

The collision pattern recorded for Stockfield Road differed slightly from the remainder of the route in that nearly all the collisions recorded involved vehicles entering or exiting the central reservation gaps to and from side road junctions colliding with main road traffic. In particular the collisions involved powered two wheelers and cyclists filtering through the traffic flow.

* Speed Related Collisions being defined as having one or more of the following contributory factors recorded within the Stats 19 form for a specific collision:

‘Exceeding speed limit’, ‘Travelling too fast for conditions’, ‘Loss of control’, ‘Aggressive driving’, ‘Careless or reckless or in a hurry’.

1.3Vehicle Speed Analysis

Full seven day count vehicle speed data were collated along the sections within 2010.

Section Link / Mean Speed
(mph) / 85%ile Speed
(mph)
A4040 Fox Hollies Road / 34.9 / 39.5
A4040 Highfield Road / 34.4 / 39.6
A4040 Stockfield Road / 37.8 / 42.8
Highfield Road / 32.3 / 37.5
Robin Hood Lane / 32.3 / 37.2

The above mean speed results indicate that vehicle speeds are more inline with a 30mph speed restriction than the posted 40mph speed limit, with the exception of Stockfield Road.

1.4Site Observations

The routes in the main comprise of two lane dual carriageways with tree lined grassed central reservations. The routes are predominately residential roads with significant amounts of on street parking present, resulting in the nearside lane in both directions being utilised for on street parking.

The exception being for the length of the 40mph speed restriction on Stockfield Road, where the character of the highway differs from the remainder of the route. The carriageway, central reservation and footways are wider and the development changes from residential to industrial. This is reflected in the observed higher travelling speeds of vehicles along this section.

1.5Recommendations

From the recorded injury accident history analysis it is noted that there is no significant speed related injury accident history present, however there is a disproportionate amount of collisions involving vulnerable road users, particularly involving pedestrians using the controlled zebra crossing facilities.

The installation of the zebra crossings within Fox Hollies Road and Robin Hood Lane do not currently accord with LTN1/95 with respect to vehicle 85%ile speeds recorded being in excess of the 35mph threshold specified.

Accordingly giving due consideration to the site observations made, along with speed and accident data analysis undertaken the existing 40mph speed limits along A4040 Highfield Road, A4040 Fox Hollies Road, Highfield Road (classified) and Robin Hood Lane (classified) should be reduced to 30mph speed limit (restricted road). This would achieve the introduction of a speed limit appropriate for the character and function of the road, along with assisting in reducing vehicle speeds to address the high vulnerable road user accident rate present. In addition it would also assist in reducing vehicles speeds and hence ensuring the existing Zebra Crossing installations do not conflict with LTN1/95 guidance on vehicle speeds.

The existing 40mph speed limit arrangement on Stockfield Road should remain as a 40mph restriction. Vehicle speeds along this section were higher than the other sections and were more in line of a 40mph speed limit, and excessive vehicle speed was attributed to only a small proportion of the collisions recorded.