Gloucestershire Local Transport Plan Annual Progress Report 2003

Appendix D

A40 Improvements and Park and Ride Contents

1 INTRODUCTION 1

2 A40/A48 HIGHNAM WOOD 4

3 A40/B4215 LINTON 5

4 A40/A417 OVER 8

5 A40/A38 LONGFORD 11

6 A40/A417 ELMBRIDGE COURT 14

7 SUMMARY AND SCHEME COSTS 18

8PARK AND RIDE PROVISION 19

9 CONCLUSION 20 1 Introduction

The A40 is a strategic east-west route across the County. As well as providing for national and regional movements, it is a major corridor through the Central Severn Vale (CSV). The A40 provides the CSV’s main link to the motorway network and it forms the northern bypass to and 2 important radials within Cheltenham. It also provides the only access to Gloucester from a large area to the west of the Severn. As a consequence the A40, particularly on the section around and to the west of Gloucester, is often congested. The A40 is managed by the Highways Agency, but detrunking orders have been issued for the entire length of the route throughout the county along with the A48. The County Council has lodged an objection to the order on the basis of capacity and safety issues along the route with particular concern around the Gloucester area and on the basis of the need to develop an integrated approach to resolving the problem. The Council has undertaken an initial assessment of the A40 from Highnam Roundabout to Elmbridge Court Roundabout. This study established a £4million package of measures for five junctions (Highnam, Linton (B4215), Over, Longford and Elmbridge Court) to achieve an increase in capacity and to pave the way for the introduction of two park and ride sites. The details of this study are included in this appendix. These measures would provide a considerable reduction in journey time and thereby assist the Government in its aim of reducing congestion on inter urban routes, bringing associated economic and environmental benefits to the area. These measures should resolve most of the County’s concerns regarding detrunking. However, it is recognised that they are only the first step in the implementation of an integrated package of measures to provide a longer term solution and to avoid the extra capacity being filled up. For these reasons a more detailed study of the A40, including the Cheltenham section, has now been commissioned. This will build on the recommendations from the first study and will look at the introduction of 2 park and ride sites for Gloucester and 1 new and 1 expanded site for Cheltenham along with bus priorities and other traffic management measures. This work will include the CSV Saturn model presently being built in a partnership between the County Council and the Highways Agency and other studies underway as part of the development of the County’s second Local Transport Plan.

Halcrow Study In October 2000, Halcrow Fox was commissioned jointly by County Council, Gloucester City Council and Tewkesbury Borough Council to develop a Park and Ride strategy for the city of Gloucester. The strategy has the following objectives: ■ To identify the most effective combination of Park and Ride sites to serve Gloucester. ■ To identify improvements to the east-west A40 strategic route to the north of Gloucester. ■ To identify in broad terms where complementary public transport measures will be required to support Park and Ride and give greater priority to public transport. This report presents the results of the A40 route assessment element of the study, identified in (b) above. The results of the other elements are presented separately. The following chapters describe the assessment of each junction along the section of the A40 assessed, while the final chapter gives details of the cost estimates for improvements proposed at these junctions.

A40 Route Assessment As part of the Park and Ride strategy, the study brief required an investigation into the existing congestion and delay experienced on the A40 to the north of Gloucester, between its junctions with the A48 at Highnam Wood and the A417 at Elmbridge Court, as shown in Figure 1.1.

1 This investigation was to focus in particular on the assessment of problems and potential solutions at the following junctions: ■ A40/A48 roundabout, Highnam Wood; ■ A40/B4215 junction, Linton; ■ A40/A417 roundabout, Over; ■ A40/A38 roundabout, Longford; ■ A40/A417 signalised roundabout, Elmbridge Court. The capacity of each of these junctions was assessed using appropriate computer software. ARCADY/5 was used to examine the roundabouts at Highnam Wood, Over and Longford. The part- time traffic signals at the A40/B4215 junction do not operate during the morning peak period, and so this junction was assessed using both the PICADY/4 and LINSIG computer programs. The signalised roundabout at Elmbridge Court was studied using TRANSYT/11. In undertaking these assessments, use was made of existing recent junction count data where possible. New data were required, however, at the Over and Elmbridge Court junctions, which were carried out in November 2000 using video camera surveys. Table 1.1 lists the surveys used in the junction assessments. Table 1.1 - A40 Junction Surveys

Location Date of Survey A40 / A48 Highnam Wood 5 July, 2000 A40 / B4215 Linton 4 April, 2000 A40 / A417 Over 21 November, 2000 A40 / A38 Longford 15 September, 1998 A40 / A417 Elmbridge Court 21 November, 2000

In addition to the junction surveys, journey time surveys were undertaken over the length of the A40 between Elmbridge Court and Highnam Wood during different time periods on 29 November 2000. Whilst this information is not sufficient to derive statistically accurate data on journey times, it does provide a valuable aid in determining when and where congestion is currently occurring on this part of the route. In each case, the parameters used in the junction models were adjusted to ensure that the model gave a reasonable representation of observed congestion and queuing. The models were then used to consider possible improvement schemes that might be introduced in order to reduce congestion.

2 Brockworth rk and Ride Pa Court Elmbridge nction Ju Innsworth Linton Figure 1.1: and Ride sites Study and Park A40 Route

3 2 A40/A48 Highnam Wood

Existing Situation This junction is located at the western end of the section of A40 studied, where the A48 trunk route from Lydney and Chepstow joins the A40 trunk route from Ross-on-Wye. It takes the form of a three- arm roundabout with an inscribed circle diameter of 75 metres, and all of the approaches to the junction are well aligned. On the east side of the junction, the A40 route from Gloucester is a dual carriageway, with a two-lane approach. The exit from the roundabout towards Gloucester also has provision for two lanes, but eastbound traffic is obliged to merge into a single lane within a short distance because of the layout of the adjacent junction with the B4215 at Linton. The approaches on the A40 (west) and the A48 are both single carriageways. The junction was modelled using the ARCADY/5 computer program. The survey results indicate that there are very low flows turning between the A40 (west) and the A48 in both peak hours, so that the great majority of traffic on both approaches turns towards Gloucester. The effect of this is that, at the entry of both arms onto the roundabout, lane usage is very unequal, so that nearly all traffic on both of these arms uses a single lane to enter the roundabout. The entry geometry entered into the ARCADY model on these arms was therefore artificially adjusted to take account of this. The results from the ARCADY assessment are shown in Table 2.1. This shows that in the evening peak period, the junction has a significant amount of spare capacity, with minimal queuing, and that the effect of the unequal lane usage is therefore marginal. In the morning peak period, however, the unequal lane usage on the A40 (west) leads to the approach becoming over-saturated, with significant queuing. Table 2.1 - A40/A48: Arcady Results, Existing Layout A40 (Gloucester) A48 (Chepstow) A40 (Ross) Max. RFC Max. Queue Max. RFC Max. Queue Max. RFC Max. Queue AM Peak 0.37 1 0.83 5 1.24 91 PM Peak 0.73 3 0.38 1 0.47 1 AM Peak (corrected) 0.37 1 1.51 229 1.37 183

Note: RFC = Ratio of Flow to Capacity Site observations, however, show that severe congestion occurs in the morning peak period on both the A40 (west) and A48 approaches, which can extend for over 1km. This queuing is, however, caused by problems generated at the A40/A417 Over roundabout, whereby traffic queues extend back to Highnam and restrict the capacity of the exit from the A40/A48 roundabout. The effect can be allowed for in ARCADY by making a manual adjustment to the capacity of the two approaches, and the effect of this adjustment is also shown in Table 2.1. A lower adjustment was made to the A40 (west) approach in order to produce queues of the right order of magnitude. Although this approach should theoretically have a lower capacity as it gives way to traffic from the A48, the slightly lower queue under these severely congested conditions results from traffic on the A40 approach forcing its way into stationary traffic queuing around the roundabout from the Gloucester exit towards the A48 entry. The results without the correction suggest that, if improvements were made to the capacity of the Over roundabout, some problems would still remain on the A40 approach from Ross in the morning peak period. This results from the imbalance of flows at the roundabout, which prevents full use of the road space on entry. The restriction of the A40 exit to Gloucester to a single lane between this roundabout and the B4215 junction at Linton may also exacerbate this situation. It is possible, however, that with the availability of a reasonable length of two-lane exit towards Gloucester, the removal of the static queuing from this exit in the morning peak period may encourage a more equal use of the entry lanes from this approach. With the current traffic flows, therefore, and provided that the proposed improvements at Over, discussed in Chapter 4, succeed in relieving the congestion that occurs at this roundabout in the morning peak period, an improvement to the existing layout at Highnam Wood may not be required.

4 3 A40/B4215 Linton

Existing Situation The A40 between the A48 roundabout at Highnam Wood and the A417 roundabout at Over is a dual 7.3m carriageway with a grassed central reserve. The B4215 from Newent, a single carriageway generally 6.0-6.5m wide, joins the A40 at Linton, although the right turn onto the A40 is not permitted. Traffic from the B4215 that wishes to turn right towards Highnam Wood is therefore required to travel east towards Over and execute a U-turn around this roundabout. The existing junction at Linton operates under part-time signal control, in which signals operate through much of the day, with the exception of the morning peak period, when it reverts to priority control. Traffic emerging from the B4215 does not come under any form of junction control, but flows freely into the nearside lane on the A40 eastbound exit. To accommodate this, traffic approaching on the A40 from the west is confined to a single lane at this junction, which forms the offside lane on the eastbound exit. For this reason, the nearside lane of the A40 between Highnam Wood and Linton is hatched off, so that traffic has to merge into the offside lane. The hatched area in the nearside lane incorporates a cycle lane on the approach to the junction. This constriction of traffic on the A40 appears to exacerbate the congestion currently observed in the morning peak on the approaches to the A40/A48 Highnam Wood roundabout, as discussed in Chapter 2. The junction has been modelled for the evening peak period using the LINSIG computer program. This analysis excludes traffic emerging from the B4215, together with the main westbound through movement on the A40, as neither of these traffic streams come under signal control. In effect, therefore, the analysis considers the conflicting requirements of the eastbound movement on the A40 and the right turn from the east into the B4215. The results of the LINSIG analysis are shown in Table 3.1, using a 60-second cycle time. Table 3.1 - A40/B4215, Linton: LINSIG Results, Evening Peak A40 (Ross) B4215 (Newent) RFC Queue RFC Queue 0.98 20 1.03 27

Note: RFC = Ratio of Flow to Capacity The results show that both of the conflicting movements are operating at about capacity, and the queue predictions are consistent with site observations. The right turn lane from the A40 (Gloucester) into the B4215 has sufficient capacity to store about 20 vehicles, so that longer queues extend into the main westbound carriageway of the A40, delaying through traffic. This occurs regularly during the evening peak period, and the speed of the westbound traffic on the A40 at this point is such that queuing traffic on the main carriageway here represents a significant hazard. As noted above, during the morning peak period, the junction reverts to priority control. An analysis using the PICADY/4 computer program indicated that the right turn from the A40 into the B4215 would have a maximum RFC (Ratio of Flow to Capacity) value of 1.55, with a queue extending up to 65 vehicles. In practice, the generally static eastbound queuing from the Over roundabout through this junction means that the normal priority rules break down. Vehicles turning right therefore have to rely on gaps being created by the eastbound queue to allow them through. In general this operates reasonably well, and as a result the observed right-turning queues tend to be considerably lower than that predicted by PICADY. The PICADY analysis does, however, indicate that any junction improvement at Over that reduced the eastbound queuing in the morning peak would have consequences for the operation of the B4215 junction. Under these circumstances, the right turn in to the B4215 would become difficult with traffic having to find gaps in the substantial eastbound flow on the A40.

5 Potential Improvements The assessment with the LINSIG program indicates that the use of traffic signals with the existing layout results in the junction operating with a Practical Reserve Capacity of –4.2% at the maximum cycle time of 120 seconds in the morning peak. The A40 eastbound approach would be close to capacity with an RFC value of 0.94 and a queue of 17 vehicles, whilst the right turn movement towards the B4215 would have a similar saturation level (RFC 0.93) and a queue length of 13 vehicles. The long cycle time together with the amount of green time required for the main eastbound flow means that delays to the right turn traffic would average 100 seconds. The junction was also assessed with the A40 eastbound carriageway operating with the full two lanes, which would necessitate the B4215 approach also coming under signal control. In the morning peak period, with a 120-second cycle time, the junction would operate at capacity. The A40 eastbound approach would be at capacity (RFC 1.00) with a queue of 51 vehicles, and the B4215 entry would also have an RFC value of 0.99 and a queue of 30 vehicles, approximately 180m from the junction. The Practical Reserve Capacity for the junction as a whole is predicted to be –10.8% under this scenario. In the evening peak the junction would operate with an improved performance. The A40 eastbound approach would have a significant reserve capacity (RFC 0.75) and a queue of nine vehicles. The right turn into the B4215, which in the current arrangement has a queue that regularly exceeds the available length of the right turn lane, would also operate with a significant improvement (RFC 0.82) and a queue of only seven vehicles. The optimum cycle time for the period is forecast at 45 seconds, at which the Practical Reserve Capacity for the junction would be 9.5%. A possible means of improving the junction performance described above is shown in Figure 3.1. This layout would utilise the two eastbound lanes for through traffic on the A40, which would be signal-controlled at all times. This would require the removal of the existing cycle lane on the A40 eastbound approach, unless further widening into the central reservation takes place on this approach. It should, however, be noted that at present the cycle lane terminates at the Linton junction, and does not continue on the eastbound exit. The proposal would also widen the eastbound exit from the junction, so allowing sufficient room to be created on the nearside to provide a merge facility for traffic from the B4215. This would again leave only two conflicting movements to be controlled by the signals, and tests with LINSIG indicate that, using a 50-second cycle time, the main eastbound flow would have an RFC value of 0.60 with a queue of eight vehicles, while the right turn into the B4215 would also be well within capacity (RFC 0.59) with a queue of only three vehicles. With the regard to the proposed eastbound merge of traffic from the B4215, Design Standard TD 22/92 of the Design Manual for Roads and Bridges, issued by the Department of Environment, Transport and the Regions, recommends alternative layouts to cater for varying merge and mainline traffic volumes. The observed traffic volumes indicate, in the morning peak period, that about 1130 vehicles per hour would be required to merge into a mainline flow of about 1500 vehicles per hour. The recommended layout for these flows on an all-purpose road includes an auxiliary lane running alongside the mainline lanes between the ‘nose’ of the merge and the taper. The merge layout shown in Figure 3.1 would meet these design standards. The length of the auxiliary lane shown is 160 metres, as recommended in TD 22/92 for a rural dual carriageway with a design speed of 100 kph or less. Linton is one of the sites considered as part of the Gloucester Park and Ride strategy, and if a site was to be developed here then it is likely that this junction would form the principal access point to the site. In this event, a significant re-design of this junction would be required, which is likely to render the improvements outlined above superfluous. Consequently, the detailed design of these improvements will need to take into account the future development of the site as outlined in the Park and Ride strategy.

6 Figure 3.1: A40/B4215 Linton - Proposed Amendments

7 4 A40/A417 Over

Existing Situation The Over roundabout forms the interchange between the A417 from Gloucester city centre, the A40 Gloucester Northern Bypass, and the A40 and A417 routes from the west and north-west. The A40 from the west is a dual carriageway with a wide central reserve, and the A417 approach from the city centre is also dual carriageway. There is a slip road which connects the A417 (Gloucester) to the A40 (west) at a merge facility some 120 metres west of the Over roundabout, so that traffic from the city centre travelling west on the A40 does not have to pass through the Over roundabout. The A417 from Ledbury and the A40 Gloucester Northern Bypass are both single carriageway routes. The Bypass flares to three lanes at the entry to the roundabout, but these are marked such that only one lane is available to traffic moving ahead on to the A40 towards Ross, even though the westbound exit has two lanes available. The surveys indicate that, in the morning peak period, 71% of traffic on the westbound approach continues towards Ross, rising to 83% in the evening peak period. The consequence is that full use of all three entry lanes available on this approach is rarely achieved. The roundabout was modelled using the ARCADY/5 computer program, and the results are shown in Table 4.1. In order to reflect the unequal lane usage on the entry from the Northern Bypass, the entry width parameter was artificially reduced in the program. Further corrections were made to the capacity of this entry in order to reproduce the observed queues on this entry. Table 4.1 - A40/A417 Over: Arcady Results, Existing Layout A40 (Ross) A417 (Ledbury) A40 GNBP A417 Gloucester Max. Max. Max. Max. Max. Max. Max. Max. RFC Queue RFC Queue RFC Queue RFC Queue AM Peak 1.18 210 1.07 30 1.23 73 0.12 0 PM Peak 0.60 2 0.31 1 1.23 127 0.33 1

Note: RFC = Ratio of Flow to Capacity The results reflect the severe queuing observed on the approach from the west in the morning peak period (already noted in Chapters 2 and 3), together with the congestion observed on the Bypass in both the morning and evening peak periods. The A417 from Ledbury is shown as slightly over capacity in the morning peak, although observations indicate that this situation only occurs for short periods. Site observations and the ARCADY results suggest that in many ways this junction is one of the key points on the A40 route north of Gloucester. Queues on the approach from the west in the morning impact on both of the main junctions further west on the A40. The section of the Bypass to the east of the roundabout, between Over and Longford, was the only section to be constructed as a single carriageway, and congestion problems are evident here in both peak periods. Potential Improvements Figure 4.1 shows a possible improvement to the approach and entry geometry on the A40 (Ross), A417 (Ledbury) and A40 Gloucester Northern Bypass. This improvement includes a reduction in the central island diameter from 54m to 46m in order to accommodate the increased number of entry lanes on these approaches. This would allow two lanes of circulating traffic around the island, which would be necessary to promote better lane usage for the high volume of right turning traffic from the A40 (Ross) to Gloucester city centre. The improvement would provide an additional lane on the A40 (Ross) approach to the roundabout, between the roundabout and the recently installed traffic signals at Over to serve a new housing development. Whilst an additional lane could not be provided on the nearside across owing to the cantilever form of the bridge deck construction, it could be accommodated by widening on the offside within the central reservation across the bridge, as shown in Figure 4.1. This would allow the movement ahead to the A40 Gloucester Northern Bypass (821 vehicles in the morning

8 peak) to use the nearside lane, with the two offside lanes occupied by the heavy right turn to Gloucester (1532 vehicles in the morning peak). The roundabout is constructed on embankment with that on the east side of the A417 from Maisemore being approximately 3m high. This embankment would need to be extended to enable widening of this approach, giving a 6m approach over the last 75m, widening to 10.5m at the roundabout entry. This would enable the nearside lane to be separated from other movements and allow two lanes to be used for the largest movement, which is ahead towards Gloucester. The Gloucester Northern Bypass approach from Longford is also constructed on embankment, incorporating a viaduct across the River Severn to the east of Over roundabout. There is scope to widen this approach between the end of the viaduct and the roundabout, in order to provide an additional lane over a distance of 110m. This would enable the right turn movement to be separated and allow two lanes to be utilised for the predominant ahead movement, making full use of the existing two-lane exit towards Ross. The ARCADY model was run with these improvements to the junction geometry, although the capacity corrections that were applied to the A417 Maisemore and A40 Longford approaches were maintained. The results, shown in Table 4.2, indicate that the operation of the roundabout would be significantly improved, with all approaches within capacity. Table 4.2 - A40/A417 Over: Arcady Results, Improved Layout

A40 (Ross) A417 (Ledbury) A40 GNBP A417 Gloucester Max. Max. Max. Max. Max. Max. Max. Max. RFC Queue RFC Queue RFC Queue RFC Queue AM Peak 0.87 7 0.80 4 0.90 8 0.15 1 PM Peak 0.44 1 0.20 1 0.65 2 0.36 1

Note: RFC = Ratio of Flow to Capacity The morning peak period would remain the critical time, when the A40 approaches from the west and the east would still be fairly close to capacity. However, it should be recognised that these results retain the capacity corrections applied in order to reproduce observed queues. It is possible that the improved geometry may provide the conditions that would enable these corrections to be reduced. These results should therefore be regarded as a ‘worst case’. Running the model with both the improved geometry and the capacity corrections removed produced a greatly improved performance. The approach from the A40 Gloucester Northern Bypass achieved an RFC value of 0.52, assuming full lane utilisation on the entry. As noted in Chapter 3, Linton is one of the sites considered as part of the Gloucester Park and Ride strategy, and if this site was to be developed for this purpose, then the Over junction would form a key point on the route into Gloucester for the Park and Ride service. In this event, it may be desirable for any improvements to the Over junction to incorporate bus priority facilities on the approaches. This might, for example, include the provision of an additional bus lane on the eastbound A40 approach, possibly with a pre-signal facility at the signal-controlled junction to the west of the roundabout.

9 Figure 4.1: – Proposed Improvements A40/A417 Over

10 5 A40/A38 Longford

Existing Situation The A38 is an important route between Gloucester and Tewkesbury to the north, and it intersects the A40 Gloucester Northern Bypass at Longford roundabout. The section of the Bypass to the west of this junction is single carriageway constructed on embankment, although to the east, between Longford and Elmbridge Court, the Bypass is built to dual carriageway standards. The results of a queue length survey carried out in September 1998 indicate that significant queuing occurs on the A38 approach from Tewkesbury in the morning peak period, and on both A38 approaches in the evening peak period. The roundabout was modelled using the ARCADY/5 computer program, and capacity correction factors were applied to some of the approaches in order to reproduce observed queue lengths. On the A38 from Tewkesbury, the great majority of traffic travels ahead towards Gloucester, particularly in the morning peak, which means that the full width of the entry onto the roundabout is not utilised, and an adjustment was made to the entry geometry to allow for this. Similarly, the offside lane on the westbound entry from the Northern Bypass is marked for right-turning vehicles (towards Tewkesbury) only. As this movement comprises a low proportion of the total entry flow, this again results in unequal lane usage on this approach, particularly in the morning peak. The results of the ARCADY analysis are given in Table 5.1. This shows that the A38 is significantly above capacity in the morning peak, and is at capacity in the evening peak. The A38 from Gloucester has particular problems in the evening peak, while the westbound approach on the A40 is at capacity during both periods. Table 5.1 - A40/A38 Longford: Arcady Results, Existing Layout A40 (Ross) A38 (Tewkesbury) A40 (Cheltenham) A38 (Gloucester) Max. Max. Max. Max. Max. Max. Max. Max. RFC Queue RFC Queue RFC Queue RFC Queue AM Peak 0.87 6 1.17 47 0.99 21 0.54 1 PM Peak 0.69 2 1.03 27 0.98 20 1.12 60

Note: RFC = Ratio of Flow to Capacity Potential Improvements This junction is more restricted in size than others along the route, so that it would not be possible to signalise the roundabout, owing to the lack of queue storage capacity within the circulatory carriageway. The junction is constructed on built up ground and is higher than the surrounding land on the south and east sides, so that the potential to widen the approaches is also limited. However, the construction of the embankments is such that some local widening of the approaches is feasible. A possible improvement scheme is shown in Figure 5.1, in which the two entries from the A38, together with the entry from the A40 (west), are widened. On the A40 (east) approach, it is noticeable that the existing lane marking arrangements reduce the available capacity of this approach. The offside lane, marked for the right turn to the A38 (north), is significantly underused as the great majority of traffic is either travelling towards Gloucester or west along the A40. Allowing ahead traffic to use either lane on this approach would improve capacity, and the improvement scheme shows a reduction in the size of the central island to permit two lanes of traffic to circulate, together with a widening of the exit onto the A40 (west). A route study undertaken by the Gwent Consultancy in August 1999 also identified both this roundabout and the A40 entry and exit on the west side of the junction as being locations of potential skid failures. This improvement scheme would provide the opportunity to rectify this deficiency.

11 The ARCADY model was re-run with the revised geometry and lane allocations, but retaining the intercept corrections used to achieve the observed queue lengths. The results, given in Table 5.2, show that the roundabout would operate with an improved performance, although some approaches would remain close to capacity. Table 5.2 - A40/A38 Longford: Arcady Results, Improved Layout A40 (Ross) A38 (Tewkesbury) A40 (Cheltenham) A38 (Gloucester) Max. Max. Max. Max. Max. Max. Max. Max. RFC Queue RFC Queue RFC Queue RFC Queue AM Peak 0.68 3 0.94 10 0.81 4 0.55 2 PM Peak 0.60 2 0.82 5 0.93 11 0.96 14

Note: RFC = Ratio of Flow to Capacity In the morning peak, some congestion would still occur on the approach from Tewkesbury, owing to the large crossflow of traffic moving east on the A40. In the evening peak, the A40 from the east and the A38 from Gloucester would also be close to capacity, with some congestion to be expected. Again it should be noted that these results, with the capacity corrections retained, represent a worst case. It is possible that the junction improvement could create the conditions that remove the need for these corrections. This would assume that full lane usage would be achieved, and it would require revision to the direction and lane signing to ensure that drivers can make an early decision on the selection of the appropriate lane. Running the ARCADY model with the intercept corrections removed indicated that the junction would operate well within capacity on all arms in both the morning and evening peak periods.

12 Figure 5.1: A40/A38 Longford – Proposed improvements

13 6 A40/A417 Elmbridge Court

Existing Situation This is a major 6-arm junction at the eastern end of the section of the A40 studied, which connects the Gloucester Northern Bypass with the main A40 route from Cheltenham and the A417 trunk route from Swindon. Both of the latter routes also connect to the M5 motorway. These three approaches are all constructed to dual carriageway standard. In addition, the B4063 route passes through this junction. To the west, it leads through the Longlevens area into Gloucester city centre, while to the east it provides an alternative route of a lower standard to Cheltenham than the A40 through the Churchdown area. The sixth arm forms an access to the government offices at Elmbridge Court. The Elmbridge Court junction is partially signalised on a permanent basis, with the three main approaches (A40 west, A40 east and A417) all subject to signal control. The three minor arms operate as conventional roundabout entries. Observations indicate some significant congestion and queuing occurs at this junction in the morning peak period, particularly on the A40 approach from Cheltenham and on the B4063 approach from Gloucester. The junction has been modelled using the TRANSYT/11 computer program, with a 56-second cycle time (as observed on site). The results of the analysis are shown in Table 6.1. Table 6.1 - A40/A417 Elmbridge Court: Transyt Results, Existing Layout

AM Peak PM Peak RFC Average RFC Average Queue Queue A40 Gloucester Northern Bypass 0.90 23 0.99 30 B4063 (Churchdown) 0.92 14 0.92 8 A40 (Cheltenham) 1.10 126 0.92 27 Elmbridge Court 0.08 0 0.16 0 A417 (Brockworth) 0.90 21 0.92 30 B4063 (Gloucester) 1.06 41 0.85 9

Note: RFC = Ratio of Flow to Capacity The results show that, in the morning peak, the A40 approach from Cheltenham is significantly over capacity, with long queues developing that can extend for over one kilometre. The B4063 from Gloucester also has some significant problems, although observations suggest that congestion on this approach is very intense over a short period in the morning peak. Conditions in the evening peak are not as congested, but the results show that the junction is close to capacity during this period. The main approaches from the Gloucester Northern Bypass and the Barnwood Link are close to or at capacity in both the morning and evening peak periods. Potential Improvements This junction already has a complex layout with signal control, so that the scope for significant improvement short of grade separation is fairly limited. Figure 6.1 shows some relatively minor improvements that might be considered at the junction. In particular, these address the A40 approach from Cheltenham, which currently experiences the most severe congestion. At present this flares from two lanes on the approach to three lanes at the entry, although queuing extends well beyond the length of the flare. The improvement proposed would extend the three lane section from its current length of 80m to about 230m, by narrowing the central reservation to 2.5m. If necessary this could also be achieved by widening on the nearside, although this would be more expensive as it would affect the underpass that exists to provide a pedestrian / cycle route between the B4063 from Churchdown with the A417 Barnwood Link.

14 A significant queue also develops on the B4063 approach from Gloucester during the morning peak period. This arm is not under signal control and vehicles consequently experience difficulty in entering the roundabout. There is, however, scope to widen the approach to a full 2 lanes over the last 75m of approach with a further local widening to 3 lanes on entry to the roundabout. The results of the TRANSYT model with these improvements are shown in Table 6.2. These indicate that the A40 approach from Cheltenham would show a marked reduction in congestion, although in the morning peak it would still be close to capacity. The approach from Gloucester would also show a significant operational improvement. In the evening peak, the Gloucester Northern Bypass also shows an improvement in capacity, which arises from the signal optimisation within the TRANSYT program allocating more green time to this approach, so that the improvements enable a more efficient co-ordination of the traffic signals. Table 6.2 - A40/A417 Elmbridge Court: Transyt Results, Improved Layout AM Peak PM Peak RFC Average RFC Average Queue Queue A40 Gloucester Northern Bypass 0.90 23 0.77 17 B4063 (Churchdown) 0.93 15 0.67 3 A40 (Cheltenham) 0.95 38 0.73 21 Elmbridge Court 0.09 0 0.16 0 A417 (Brockworth) 0.90 21 0.92 30 B4063 (Gloucester) 0.81 8 0.74 5

Note: RFC = Ratio of Flow to Capacity Consideration has also been given to the potential for fully signalising the junction (with the exception of the Elmbridge Court entry). Tests indicated that the widening of the B4063 approach from Gloucester would still be required, as the use of the existing single lane approach and two-lane entry would produce significant congestion. The TRANSYT results given in Table 6.3 therefore assume the signalisation of the two B4063 approaches in addition to the improvement scheme shown in Figure 6.1. Table 6.3 - A40/A417 Elmbridge Court: Transyt Results, Fully Signalised AM Peak PM Peak RFC Average RFC Average Queue Queue A40 Gloucester Northern Bypass 0.96 28 0.77 17 B4063 (Churchdown) 0.86 13 0.77 9 A40 (Cheltenham) 0.95 38 0.73 21 Elmbridge Court 0.10 0 0.16 0 A417 (Brockworth) 0.90 21 0.92 30 B4063 (Gloucester) 0.93 15 0.68 9

Note: RFC = Ratio of Flow to Capacity These show some mixed results, giving an improvement at the Churchdown approach in the morning peak, but with a slight decrease in performance in the evening peak (although it would still be well within capacity). More importantly, the approach from Gloucester would experience greater congestion in the morning peak, operating just below capacity. The Barnwood Link Road and Gloucester Northern Bypass approaches would be relatively unaffected by the proposed improvements, and so would remain close to capacity. It is suggested

15 that the potential to improve these arms might form a subsequent phase of improvement to the junction. Initially, the improvements shown in Figure 6.1 could be constructed, together with possible improvements to the carriageway markings through the roundabout. At present, while motorists are given clear signing concerning lane choice on the three main approaches to the roundabout, the route that should be taken through the roundabout is much less clear. Consideration could therefore be given to the development of appropriate carriageway markings, such as worded destinations (both on the approaches and within the roundabout) and/or ‘spiral’ markings, in order to make the most efficient use of the available circulatory carriageway within the signalised sections of the roundabout. The Elmbridge Court roundabout was also identified in the Gwent Consultancy’s report as being a potential skid failure location, and it may be opportune for any redesign of carriageway markings within the junction to be accompanied by a resurfacing scheme to rectify this. Other potential improvements might be explored in conjunction with a potential Park and Ride site at Elmbridge Court, as discussed in Section 4.9. These might include the introduction of a new junction onto the A40 Golden Valley Bypass to the east of this junction, possibly with the use of the existing Elmbridge Court entry by Park and Ride traffic. The detailed design of any improvements to the Elmbridge Court junction should take into account the traffic patterns that would arise from the introduction of the Park and Ride site.

16 Figure 6.1: Court A40/A417 Elmbridge – Proposed Improvements

17 7 Summary and Scheme Costs

Summary The assessment of the capacity of the A40 route between Highnam Wood and Elmbridge Court found that the main points of peak period congestion currently occur at the Over, Longford and Elmbridge Court roundabouts. An improvement scheme at Over could be implemented to provide additional lanes on the eastbound and westbound approaches. The consequence of increasing the junction capacity at Over would be to create problems at the B4215 junction at Linton through the removal of the slow-moving queue through this junction in the morning peak period. Some road widening in conjunction with the implementation of signal control during this period is also proposed, with traffic entering from the B4215 subject to merge control. The design of the improvements at both of these junctions could be subject to review, however, if it is intended to introduce a Park and Ride facility at the Linton site. Improvement schemes at Longford and Elmbridge Court have been identified involving the widening or realignment of some approaches to the roundabout. The design of improvements at Elmbridge Court need to be reviewed to allow for the proposed Park and Ride facility at this location. Cost Estimates Estimates of the cost of carrying out the improvements outlined in the preceding chapters and illustrated on Figures 3.1 – 6.1 are given in Table 7.1. These cost estimates, at 2001 price base, relate to the actual civil engineering works required to construct the schemes. They do not make allowance for any alterations required to drainage or services. In addition, the traffic management costs necessary to allow their construction on a major route such as the A40 could be significant. Additionally, design and supervision costs would probably form an additional 10% of the total construction cost. Table 7.1 - A40 Junction Improvement Schemes: Cost Estimates

Junction Estimated Construction Cost at 2001 price base A40/B4215 Linton £77,700 A40/A417 Over £203,900 A40/A38 Longford £67,000 A40/A417 Elmbridge Court £171,600 To tal £520,200

18 8Park and Ride Provision

As can be found in the previous pages, a number of junction improvements have been identified on the A40 trunk route to the north of Gloucester, between the A48 at Highnam and the A417 at Elmbridge Court. The aim of these improvements is to improve the capacity of these junctions and thereby relieve the existing congestion that occurs on a regular basis. The cost of constructing these improvements (excluding drainage/service alterations, traffic management and design and supervision) is estimated to be about £520,000. It is recognised, however, that these improvements are relatively minor, and that accordingly the benefits that will accrue from these improvements are likely to be fairly modest. It is considered that the scope for introducing more significant improvements at these junctions is relatively limited, for several reasons: The Elmbridge Court junction is a complex six-arm roundabout that is already partially controlled by traffic signals on a permanent basis. Tests on the potential for signalling all of the approaches showed little improvement in capacity over and above those resulting from the improvements proposed. It is likely, therefore, that the only means of obtaining any significant improvement in capacity at this junction would be through some form of grade-separation. The A38 Longford roundabout is too small to be signalised, and it has a constricted layout with adjacent embankments and residential developments that would make it very problematic to enlarge the junction sufficiently. The A417 Over roundabout is also too small to be signalised in its current form. The A40 is constructed on a viaduct across the eastern arm of the River Severn immediately to the east of the junction, while it crosses the western arm of the River Severn via Over Bridge just to the west of the junction. These constraints, together with the embankments on the A417 approaches, make it difficult to enlarge the junction sufficiently to introduce more significant improvements. It is recognised, therefore, that the benefits arising from the proposed junction improvements are likely to be relatively short-lived, owing to general growth in road traffic. Whilst more significant improvements may be feasible, they are likely to be very costly and potentially damaging in environmental terms. An alternative means of obtaining more significant capacity improvements would be to promote a Park and Ride policy for Gloucester City Centre, which would be more in keeping with national and local transport policies. During peak periods, the A40 trunk route carries a significant volume of car- borne commuter traffic bound for Gloucester City Centre, which makes a significant contribution to the existing levels of congestion at the junctions considered. In particular, the A40 Golden Valley Bypass carries a large amount of such traffic from the Cheltenham urban area and the M5 motorway, which impacts upon the Elmbridge Court junction. In addition, there is evidence from roadside interviews undertaken in the area that a considerable proportion of this commuter traffic travels along the A40 Gloucester Northern Bypass to Longford in order to access the City Centre via the A38, rather than use the more direct (but slower) route through the Longlevens suburban area, so affecting the capacity of the Longford roundabout as well. The introduction of Park and Ride facilities in this area would result in the removal of a proportion of the commuting traffic from the highway network, thus relieving congestion and extending the life of the identified junction improvements. The Gloucester Park and Ride strategy has identified a site close to the Elmbridge Court junction, either to the south or north of the A40, as being the most promising in terms of potential patronage. This would be ideally placed to attract drivers travelling into Gloucester from the Cheltenham urban area and the M5 motorway. Given the capacity limitations of the existing Elmbridge Court roundabout, the introduction of a Park and Ride site at this location would almost certainly require the construction of a new signal- controlled junction on the A40 to the east of the existing junction. In order to increase the attractiveness of the facility, it is also anticipated that bus priority measures would need to be introduced between the site access and the existing junction. Assuming a parking provision for 700 vehicles as an initial phase, the cost of constructing this Park and Ride site together with site access onto a new junction on the A40 is estimated to be in the region of £2,500,000. Significant benefits would be obtained by providing a Park and Ride facility at Linton. This site and Elmbridge Court are being investigated as part of a potential major scheme bid for the second LTP.

19 9 Conclusion

This short report sets out the improvements that are currently feasible for the main junctions on the A40 between Highnam Wood and Elmbridge Court Roundabouts identified in the 2000 study. It is proposed to review this work to ensure the proposed improvements are still appropriate. In response to the Government’s new agenda which involves investigating alternative improvements prior to submitting major road building schemes, this report also details a Park and Ride improvement at Elmbridge Court Roundabout. A bid is therefore made through this LTP Third Annual Progress Report (APR) to implement these improvements in the absence of the Highway Agency’s management plan. The intention is to work closely with the Highways Agency to develop these schemes. The schemes are relatively minor in nature and it recognised that implementation of Gloucester’s Park and Ride strategy is essential to reduce congestion and enable the development of the city in the future. The review of the design will take the needs of Park and Ride into consideration. A detailed study on Park and Ride and associated bus priority measures is underway. The Highways Agency will be closely involved in the review, and development of these proposals in the absence of their own strategy. These proposals will therefore address the worst congestion problems in the short term and form the basis of a longer term solution by enabling the introduction of Park and Ride. The sum required over the remaining two years of this LTP is £4 million. A sum of £1.290 million has already been allocated for the years 2001/2002 to 2005/2006 within the settlement received in December 2000. Therefore, an additional bid is made as follows:

2004/05 2005/06 Total £’000 £’000 £’000 Additional Bid 1,500 2,500 4,000

20 For more details please contact:

Gloucestershire County Council Environment Department, Transport Planning, Shire Hall, Gloucester GL1 2TH Tel: 01452 426793 Fax: 01452 426927 email: [email protected] website: www.gloucestershire.gov.uk/ltp/