This subject has come up on several occasions so I thought others might be interested to read the Email reply I recieved when I asked the Highways Agency to produce the results of their time trials on the Northamptonshire stretches of the A14 which has resulted in a permanent
overtaking ban in the area.
Please note that the results were inconclusive but we still got a ban
I refer to your email to the Highways Agency Information Line dated 21 December regarding the HGV restriction along the A14 in Northamptonshire.
In June 2006, as part of the Highways Agency’s strategy to tackle congestion, Ministerial approval was given for the introduction of a trial restricting HGVs from overtaking between the hours of 6am and 8pm on a 3.2km length of the eastbound carriageway of the A14 in Northamptonshire and on a 2.4km westbound length. The scheme for the A14 was promoted to see whether restricting HGVs to the nearside lane when travelling up gradients could improve journey times.
The results from the post-opening evaluation (a copy of this report is enclosed as requested) show that the average journey-times for westbound traffic improved across all time periods for both non-HGVs and HGVs. For eastbound traffic, journey times for both non-HGV and HGVs were similar to before the trial, except in March/April 2008 at the end of the trial when there was an improvement indicating a possible change in the trend.
The average time-savings are relatively small as they are reported over the short length of the trial. However, they do not reflect the perceived improved journey experience for non-HGV drivers, as slow-moving HGVs are less likely to manoeuvre and overtake using lane two.
It is considered that Highways Agency’s objective of improving journey times is sufficient to justify the trial being made permanent and a Traffic Regulation Order restricting lorries to lane two of the trialled section of A14 was implemented on 2 October 2008.
The Highways Agency has consulted with the Road Haulage Association and the Freight Transport Association throughout the scheme.
I hope this information has been of some use to you but if I can be of further assistance then please contact me. Alternatively you may wish to contact the Route Performance Manager for this section of the A14, Paul Sinfield. Paul can be contacted by email on paul.sinfield@highways.gsi.gov.uk or on 01234 796135. However please be aware that Paul is currently out of the office until 5 January 2009.
Kindest regards
, Route Performance Administrator - Area 8
Highways Agency | Woodlands | Manton Lane | Bedford | MK41 7LW
Tel : +44 (0) 1234 796071
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Conclusions
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In terms of eastbound traffic:
o AM Peak: Overall journey-times for non-HGVs have reduced across all four surveys when compared to the situation prior to the implementation of the journey-time trial. Journey-time savings are up to 15 seconds. The journey-time for HGVs have increased (in all but the final survey, during which it decreased by 4 seconds) by up to 15 seconds in the first three quarters.
o Off Peak: Average journey-times for non-HGVs during the off peak period have generally increased by between 1 and 16 seconds. A similar situation has been recorded for HGVs with average journey-time increases of between 3 and 11 seconds. The March/ April 2008 survey does not follow this trend as it shows a decrease of up to 10 seconds.
o PM Peak: Negligible change for non-HGVs with a slight increase in journey time of up to 2 seconds but in the final survey a decrease of 17 seconds. The results indicate an increase in average journey-times for HGVs by some 8 - 22 seconds in the first three surveys, but a decrease of 4 seconds in the final quarter.
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Overall the results would tend to indicate that the Experimental TRO has not offered any major improvement in terms of average journey-time for traffic travelling eastbound. The results generally suggest that both non-HGV and HGVs experienced increased journey-times relative to before the Experimental TRO came into force in the first three quarters but in the latest survey it shows an improvement.
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In terms of westbound traffic:
o AM Peak: In common with the eastbound traffic, overall journey-times for non-HGVs have reduced across all four surveys when compared with the ‘Before’ situation, with average journey-time savings of between 4 and 21 seconds. The relative average journey-time for HGVs has also improved with a journey-time saving of up to 10 seconds.
o Off Peak: The off-peak results also indicate journey-time improvements for non-HGV traffic of between 8 and 20 seconds. HGVs also show an improvement although the impact is marginal. The results show reductions of up to 11 seconds.
o PM Peak: The situation for non-HGVs broadly matches the AM peak with an average journey-time saving of between 9 and 22 seconds. This saving is also found for HGVs where the results indicate a decrease in average journey-times by some 6 - 20 seconds.
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Overall the results would indicate that the Experimental TRO has offered some improvement in terms of average journey-time saving for traffic travelling westbound across all time periods, for both Non-HGVs and HGVs alike.
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The Police have operational difficulties with enforcement, as there is a lack of lay-bys to pull a vehicle over to deal with an offence. They have raised the issue of the difficulties drivers may face seeing the signs, as they can be obscured by larger vehicles in lane one, however the existing signing is in excess of standards on the instruction of HA (SSR). They have asked if one or more of the journey-time trials are made permanent then the number and location of signs should be reviewed, but it is considered there could be constraints, which would not permit any further enhancement.
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In spite of limited enforcement the restrictions have generally been complied with and there is no evidence that an increased risk of accidents has resulted.
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The improved journey-times could however be accompanied by a related increase in average speed. While this is an possible outcome of providing less congested conditions, it might be accompanied by increased potential for some drivers to approach the legal speed limit or exceed it.
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Although the average journey-time-saving highlighted by the surveys can be considered to be relatively small in most cases, the numerical values are unlikely to reflect potential benefits in terms of improved journey experience for some Non-HGV drivers as the restriction should reduce significantly slow moving HGVs manoeuvring and overtaking using lane two.
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The likelihood of increased HGV convoys in lane one may encourage some non-HGV drivers previously content to follow at an equivalent speed in lane one to alter their driving behaviour and use lane two. The Police have commented on the fact that significant numbers of heavy goods vehicles use the A14 and a fair proportion can be in the abnormal category in terms of weight, which could cause longer convoys of HGVs and also encourage more non-HGV drivers to overtake.
I am sorry this is a bit long winded but the complete report is about 20 pages long
Annitram