Help Forum

Help requested posted on 9th August 2013:

Speed Limit Appraisal Tool

I have downloaded the DfT speed limit appraisal tool (SLAT) and had a few problems using it. One error gave the message to contact the SLAT support team but no contact details are given. When I successfully ran the appraisal in the software, the results seemed very surprising. Has anyone had experience of using this software or know how to contact the SLAT support team? The guidance note just gives a general DfT switchboard number.

Mark Gregory

Reply to this request

Response posted on 9th August 2013 by:
Kate Carpenter
T: 07920 143940


yes to all! we've used it, had problems, approached the 'help' support and found there isn;t one. I approached a DfT contact who advised that there was an intention to have a support facility but in practice there is none. We got errors as well as queries about results. sadly for now we're on our own! frustrating as with cash-strapped budget, assessments most likely to be done for the most tricky sites and/or most politicaly sensitive where results most critical!

Response posted on 12th August 2013 by:
Pat Francis
Buckinghamshire County Council
T: 01296 382437


We had problems getting it set up initially and
haven't yet managed to get a set of results yet - seems incredibly complex. Thought perhaps it was just a local problem with our set up- now reassured that this isn't the case!
Is there a need to lobby DfT re this?

Response posted on 14th August 2013 by:
Duncan Lord
T: 02476 690900

DfT Speed Limit Appraisal Tool

We have not been able to get it to work properly as it is so user unfriendly. I contacted Stephen Hammond MP about it as there is no DfT Contact given in the user guidance to see if we could get any help. Got this reply!

Dear Mr Lord,

Dft speed limit appraisal tool

Thank you for your email of 30th July to Stephen Hammond about the speed limit appraisal tool. I have been asked to reply.

I have noted your comments. We were already aware that the tool needs to be easier to load and to use and so we are currently commissioning work to rectify it.

Watch this space!!!!

Response posted on 14th August 2013 by:
Duncan Lord
T: 02476 690900

DfT Speed Limit Appraisal Tool

Sorry, Should have said the response was from Charlotte Bradford at the DfT, but without any direct contact details.

Response posted on 14th August 2013 by:
Duncan Knox
Surrey County Council
T: 0208541 7443

DfT Speed Limit Appraisal Tool

We have not been able to get it to work in Surrey either. I don't really think that the approach is fit for our purpose anyway. Within Surrey decisions over highways schemes including speed limits are delegated to local committees of elected members who are provided with a budget and are advised by highways engineers. Our speed limit policy sets the criteria within which a local committee can decide a new speed limit based upon the existing speed and how successful a new speed limit is going to be. Our Members are often under a lot of pressure from local people to change a speed limit, and I just don't think an economic cost benefit appraisal based on small margins of delay, emissions etc is of any interest to members or residents - they just want a lower speed limit and their road to reduce speeds and rightly or wrongly will not really care about the cost/ benefit to wider society. What is useful however are the equations in the appendix that provide an estimate of the likely reduction in speeds following a change in speed limit.

Response posted on 19th December 2014 by:
Partha Parajuli


SLAT in Queensland Australia

I have similar experience with QLIMITS, an appraisal tool used in Queensland Australia. Setting speed limit is not merely a technical process and tools developed are widely misused by practitioners. For that reason, I see little benefits in developing any computerised tool for speed limit appraisal.

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