A40 new 40 mph average speed limit
Request ID: FOI-1702-1819
Date published: 22 October 2018
You asked
As of the start of this month, the average speed check speed limit on the A40 in the section that previously was 50 mph and then temporary 30 mph, is now 40 mph(section from approx Polish war Memorial Roundabout to Perivale).
Could you please confirm if this 40 mph limit is also temporary? and if so why it is in place? As the temporary 30 mph limit was there to monitor the central reservation and the monitoring is now complete, when will the central reservation be replaced/repaired?
If the new 40 mph speed limit is not temporary, why has the speed limit been reduced from the previous 50 mph? How many serious accidents were there on this section whilst the limit was 30 mph? in order to warrant a 10 mph reduction in the speed limit of a 3 lane dual carriageway in a section of it where, unlike from Perivale onwards, houses are not directly accessible from it, i.e there is a slip road in front of the houses in this section, or there are no houses at all.
In a previous FOI request from another individual you stated the reason the 30 mph limit was put in place was "To ensure that safety of all road users is maintained we implemented a 30mph speed limit while we investigate the least disruptive way and time to replace the central barriers. "
How would reducing a speed limit impact your investigation?
Were accident levels monitored during the investigation? what other items were monitored during the investigation?
We answered
Dear
TfL Ref: FOI-1702-1819
Thank you for your email received by Transport for London (TfL) on 25 September 2018.
Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. I can confirm we hold some of the information you require. You asked:
Could you please confirm if this 40 mph limit is also temporary? and if so why it is in place? As the temporary 30 mph limit was there to monitor the central reservation and the monitoring is now complete, when will the central reservation be replaced/repaired?
If the new 40 mph speed limit is not temporary, why has the speed limit been reduced from the previous 50 mph? How many serious accidents were there on this section whilst the limit was 30 mph? in order to warrant a 10 mph reduction in the speed limit of a 3 lane dual carriageway in a section of it where, unlike from Perivale onwards, houses are not directly accessible from it, i.e there is a slip road in front of the houses in this section, or there are no houses at all.
In a previous FOI request from another individual you stated the reason the 30 mph limit was put in place was "To ensure that safety of all road users
is maintained we implemented a 30mph speed limit while we investigate the least disruptive way and time to replace the central barriers. "
How would reducing a speed limit impact your investigation?
Were accident levels monitored during the investigation? what other items were monitored during the investigation?
The 40mph is a permanent speed limit change. The limit was changed because this is the maximum speed, our risk assessments taking into account the unique operation of the A40 at this location have concluded you can have a dual or larger carriageway without a vehicle restraint system. The defective barrier is potentially no longer capable of restraining a vehicle impact at 50mph correctly hence the need for a reduction anyway on safety grounds irrespective of houses or slip roads. Following a detailed inspection of the barrier it was considered safe to raise the speed limit to 40mph until the barrier is replaced or removed. At this current time there are no plans to replace the barrier.
The speed limit was reduced for public safety not to enable the investigation, as safety is our number one priority.
Accident levels were not monitored during the investigation and neither was there a requirement to do so. The speed limit was reduced for public safety as there is no requirement for safety fencing on a 40mph or slower dual carriageway. As per our contract requirements the carriageway has a safety inspection every 28 days.
If this is not the information you are looking for, or if you are unable to access it for some reason, please do not hesitate to contact me.
Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.
Yours sincerely
Eva Hextall
FOI Case Officer
FOI Case Management Team
General Counsel
Transport for London
As of the start of this month, the average speed check speed limit on the A40 in the section that previously was 50 mph and then temporary 30 mph, is now 40 mph(section from approx Polish war Memorial Roundabout to Perivale).
Could you please confirm if this 40 mph limit is also temporary? and if so why it is in place? As the temporary 30 mph limit was there to monitor the central reservation and the monitoring is now complete, when will the central reservation be replaced/repaired?
If the new 40 mph speed limit is not temporary, why has the speed limit been reduced from the previous 50 mph? How many serious accidents were there on this section whilst the limit was 30 mph? in order to warrant a 10 mph reduction in the speed limit of a 3 lane dual carriageway in a section of it where, unlike from Perivale onwards, houses are not directly accessible from it, i.e there is a slip road in front of the houses in this section, or there are no houses at all.
In a previous FOI request from another individual you stated the reason the 30 mph limit was put in place was "To ensure that safety of all road users
is maintained we implemented a 30mph speed limit while we investigate the
least disruptive way and time to replace the central barriers. "
How would reducing a speed limit impact your investigation?
Were accident levels monitored during the investigation? what other items were monitored during the investigation?
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