Highways Agency - Safe roads, Reliable journeys, Informed travellers
Executive Summary
The A10 Wadesmill, High Cross and Colliers End Bypass opened on 8th October 2004. The trunk road scheme provides an alternative route for traffic travelling through the villages of Wadesmill, High Cross and Colliers End on the A10 route between Ware and Puckeridge in Hertfordshire. 'Before' and 'After' traffic data was collected before and immediately after opening to evaluate the effects of the bypass on the surrounding area.
Figure 1.0 - Weekday traffic flows 'before' and 'after' scheme opening (JPG 222KB)
The main effects of the scheme opening are as follows:
- The bypass carried around 23,000 vehicles per day after opening in November 2004 and there are significantly reduced daily traffic volumes on the bypassed section of the A10 between Ware and the A10/A120 roundabout, clearly indicating that the scheme has been successful in routing approximately 21,000 vehicles away from the old A10; which represents an 80-85% reduction in traffic levels through the three villages;
- Traffic on the A120, North of the scheme, has increased by 2,200 vpd since the opening of the bypass. Evidence from traffic counts strongly suggests that this is due to long distance strategic re-routing, as the bypass is now more appealing compared to the old A10;
- Traffic on local roads on the bypassed section of the A10 have also been reduced, with the most significant impacts on Anchor Lane and Cold Christmas Lane, which have had reductions in traffic of 1,900 vpd (36%) and 650 vpd (62%) respectively. The reduction on Anchor Lane is assumed to be due to traffic re-routing onto Westmill Road (A602) to join onto the bypass;
- The proportion of HGV's through the villages has decreased from 8-10% to 4-5%, indicating that the bypass has clearly been successful in re-routing HGV's out of these villages; and
- Journey time data suggests that time savings of around 2 minutes is being observed for journeys from the A10/A120 Standon Hill roundabout to the A10/A1170. The exception is for Soundbound trips in the PM peak where savings of 6 minutes are being observed.
Introduction
1.1 This report outlines the results of traffic surveys carried out to monitor the effects of the A10 Wadesmill, High Cross and Colliers End Bypass which opened on October 8th 2004. The trunk road scheme provides an alternative route for traffic travelling through the villages of Wadesmill, High Cross and Colliers End on the A10 route between Ware and Puckeridge in Hertfordshire.
1.2 Figure 1.1 outlines the location of the bypass that diverges from the existing A10 at the northern end of the Ware Bypass and rejoins the trunk road at the roundabout at Puckeridge. The scheme consists of a 7.5 km long new section of dual carriageway and includes a road bridge over the River Rib, together with 8 other bridges, underpasses and culverts. A detailed plan of the scheme is shown in Figure 1.2.
1.3 The objectives of the scheme were defined in the Scheme Appraisal Summary Table (AST) and can be summarised as follows:
- Remove 90% of the existing traffic from the villages of Wadesmill, Colliers End and High Cross (combined population approx 1,400), returning the A10 to the local community;
- Reduce delays and disruption to through traffic, created by a bottleneck as a result of a single carriageway road through the villages in between dual carriageway sections South of Wadesmill and North of Colliers End;
- Improve local air quality and reduce local noise levels; and
- Improve safety conditions for pedestrians and cyclists in the villages.
1.4 'Before' and 'After' traffic data was collected from Highways Agency, Hertfordshire County Council and Atkins traffic count sites immediately prior to and after the opening of the bypass, in order to evaluate the effects of the scheme opening on both local and strategic traffic routeing patterns in the East Hertfordshire area.
1.5 Chapter 2 of this report discusses the data collected as part of the TIS study. Chapters 3 and 4 summarise the main results and conclusions.
Figure 1.1 - Location of the A10 Wadesmill, High Cross and Colliers End Bypass (JPG 219KB)
Figure 1.2 - Detailed Plan of the A10 Wadesmill, High Cross and Colliers End Bypass (PDF 1.0MB)
Data Collected
2.1 The Traffic Impact Study (TIS) for the A10 Wadesmill, High Cross and Colliers End Bypass included the following surveys:
'Before' Surveys
- Traffic data from 12 Hertfordshire County Council permanent traffic count sites on County roads, 4 of which undertake continuous monitoring with the remaining 8 monitoring for one week per year in June;
- Traffic data from 3 Highways Agency permanent traffic count site locations;
- Nine temporary Automatic Traffic Count (ATC) surveys (tubes), five of which were conducted by Hertfordshire County Council, with the remaining four organised by Atkins;
- Manual turning count data on two junctions on the A10; and
- Journey time surveys undertaken in June 2002 on the existing A10 route from the roundabout with A120 towards Standon Hill to the intersection with the A1170.
'After' Surveys
For the Traffic Impact 'After' study it was not considered necessary to replicate all of the counts in the extensive programme conducted for the 'Before' study, and therefore a more appropriate count programme was adopted for this report. This report provides an initial assessment of the impact of the bypass in the immediate two months after opening. A more comprehensive comparison of all count sites assessed in the 'Before' study will be conducted for the 'One Year After' Study which provides a more in depth analysis of the impacts of the scheme;
- Seven temporary Automatic Traffic Count tube surveys, five of which were conducted by Hertfordshire County Council, with the remaining two organised by Atkins;
- Traffic data from 3 Highways Agency permanent traffic count site locations which includes one additional Highways Agency permanent ATC site on the new A10 Wadesmill, High Cross and Colliers End Bypass;
- Manual turning count data for two junctions on the A10; and
- The same journey survey route on the A10 was re-surveyed, in November 2004, with an additional journey time survey route via the new bypass.
2.2 The details of the 'Before' and 'After' surveys used in the TIS are described below, and illustrated in Figure 2.1 overleaf.
Figure 2.1 - Traffic Impact Study Count Sites (JPG 227KB)
Traffic Count Sites
2.3 Figure 2.1 shows the locations of the count sites surveyed for comparison in the Traffic Impact Study.
Automatic Traffic Counts
2.4 There were 2 Highways Agency permanent ATC sites located on the existing A10, plus the one installed on the A10 bypass. For the 'Before' surveys these sites counted for a period of 4 weeks during June 2003, and similarly, for the 'After' survey data a four week period was collected from 11th October. The locations are as follows:
- A10, North of Puckeridge and before Hay Street;
- A10, South of Ware; and
- A10 Wadesmill, High Cross and Colliers End Bypass.
2.5 Two temporary ATC sites were placed by Paul Castle Consultancy to the South of the bypass, and these were located on the:
- A10 between A602 junction and Moles Interchange; and
- A1170 between Quincey Road and Moles Interchange.
2.6 There were five temporary tube sites installed by Hertfordshire County Council on five local feeder roads to the A10 around Wadesmill, High Cross and Colliers End. For the 'Before' surveys the sites were surveyed for three weeks in October 2003, and for the 'After' surveys two weeks between 1st November 2004 until the 14th November was collected. The locations are as follows:
- East of the A10 on Cold Christmas Lane, Thundridge;
- West of the A10 on Barwick Lane, Standon Green;
- East of the A10 at Barwick Lane, Barwick;
- East of the A10 on Dowsetts Lane, Colliers End; and
- West of the A10 on Old Hall Green Lane, Puckeridge.
2.7 There were 4 Hertfordshire County Council permanent ATC sites with continuous data which were used for the study. For the 'Before' surveys three of these sites counted for a period of 4 weeks during June 2003 with one counting during April 2003. The 'After' survey data was collected for two weeks between 1st November to 14th November. These locations are as follows:
- A1184 Cambridge Road at Sawbridgeworth;
- A414 Eastwick Road, West of Harlow;
- A602 at Bragbury End, near Stevenage; and
- B1368 at Dassels Hill, Hay Street.
Manual Classified Counts
2.8 Manual Classified Counts were conducted at two sites for a 12 hour period between 07:00 and 19:00. These were at:
- A10/Standon Hill, which included additionally the A10 Bypass in the 'After' study; and
- A10/B158 Anchor Lane.
2.9 The 'Before' counts were conducted on the 20th June 2002 with the 'After' counts being conducted on the 2nd November. Vehicles were classified into car, van, other goods vehicles 1 (OGV1), other goods vehicles 2 (OGV2) and bus.
Journey Time Surveys
2.10 Journey time surveys were undertaken on two routes, identified as 'Red' and 'Blue' routes, which are illustrated in Figure 2.2. The 'Red' route represents the existing route through Wadesmill, High Cross and Colliers End, from A120 Standon Hill/A10 roundabout to A1170/A10 intersection. The 'Blue' route is the length of the new bypass. 'Before' journey time surveys previously conducted on Thursday 20th June were used for comparison with surveys post scheme opening on Tuesday 2nd November. The surveys were undertaken over the AM peak (0730-0900 hours), PM peak (1700-1900 hours) and an inter-peak period (1000-1130 hours).
Figure 2.2 - Journey Time Survey Routes (JPG 412KB)
Summary of Results
Traffic Flows
3.1 Figure 3.1 below and Figure 3.2 overleaf summarise the 'Before' and 'After' traffic data using weekday, 24 hour two-way traffic volumes. A summary results table is included in Appendix A of this report. The 'Before' counts have been adjusted to reflect third quarter 2004 traffic levels to ensure the conclusions drawn take into account seasonality and normal traffic growth. This has been done by using the seasonally adjusted traffic growth index to determine normal background growth between the count data and an index to adjust the average daily traffic flow based upon monthly seasonal variations in traffic flow. Where 12 hour MCC counts were utilised on the old A10 these were factored up to 24 hour flows by using the ratio of 12 hour to 24 hour flows derived from 24 hour ATC counts obtained for the A10.
3.2 Traffic flows on the A10 through Wadesmill, High Cross and Colliers End before the bypass was between 24,000 to 27,500 vehicles per day (vpd). After opening, the traffic flows through these three villages dropped to between 4,000 to 5,000 vpd, with the bypass carrying around 23,000 vpd.
3.3 The site west of Sawbridgeworth shows no real change in traffic volumes (-100 vpd), and the site west of Harlow shows traffic volumes have increased by 3,000 vpd. These two sites together suggest that vehicles travelling between Hertford and Bishop's Stortford / Stansted have not re-routed via these two roads, and the extra 3,000 vpd on the A414 is assumed to be due to traffic growth in the area.
Figure 3.2 - Weekday Traffic Flows 'Before' & 'After' Scheme Opening for the Local Area (JPG 222KB)
3.4 There are also decreases on the local feeder roads to the A10 in those villages, with the B158 (Anchor Lane) reducing from 5,300 vpd to 3,400 vpd, and flows on Cold Christmas Lane more than halving from 1,050 vpd to 400 vpd. The reduction on Anchor Lane is assumed to be due to traffic re-routing onto Westmill Road (A602) to join onto the bypass.
3.5 The traffic flows also indicate a 14% increase in traffic (from 15,300 vpd to 17,500 vpd) on the A120 approaching the A10/A120 roundabout. Evidence from traffic counts strongly suggest that this increase of 2,200 vpd since the opening of the bypass is due to long distance strategic re-routing, as the bypass is now more appealing compared to the old A10.
Table 3.1 - Traffic Volumes across the A10 corridor
|
AWT | ||||
|
Site |
Before |
After |
Change |
% Change |
|
Old A10 South of Stanton Roundabout |
25,400 |
4,700 |
-20,700 |
-81.5% |
|
A10 Bypass |
- |
22,800 |
22,800 |
N/A |
|
Total |
25,400 |
27,500 |
2,100 |
8.3% |
|
A10 between A602 & A1170 junctions |
21,300 |
25,000 |
3,700 |
17.4% |
|
A1170 between Ware A10 |
6,700 |
8,000 |
1,300 |
19.4% |
|
Total |
28,000 |
33,000 |
5,000 |
17.9% |
3.6 From Figure 3.2 and Table 3.1 it can be clearly seen that:
- There is an approximate 8% increase in traffic along the corridor between Ware and the A10/A120 roundabout after the opening of the bypass; and
There is some indication that flows south of the bypass on the corridor comprising of the A10 and A1170 approaching Moles Interchange have increased by 18%.
3.7 This higher increase compared to the increase in flows on the bypass and bypassed villages is likely to be due to the creation of an interchange between the A10 Southbound carriageway and A1170 at Moles Interchange, resulting in some re-routing of traffic travelling Southbound towards the A602 on the A10 from the A1170.
3.8 Count data from six of the outer lying sites are shown in Table 3.2 below. It should be noted that traffic at some of these sites is likely to be influenced by factors other than the bypass.
Table 3.2 - Outer lying Count Site Data
|
Site |
AADT | ||||
|
Number |
Description |
Before |
After |
Change |
% Change |
|
1420/1 |
A10 Ware |
46,700 |
50,200 |
3,500 |
7.5% |
|
1450/1 |
A10 Hay Street |
17,000 |
18,300 |
1,300 |
7.6% |
|
342 |
Dassels Hill, Hay Street |
3,200 |
3,000 |
-200 |
-6.3% |
|
228 |
A414 Eastwick Road, west of Harlow |
31,100 |
34,100 |
3,000 |
9.6% |
|
724 |
A1184 Cambridge Road, Sawbridgeworth |
22,400 |
22,300 |
-100 |
-0.4% |
|
260 |
A602 Bragbury End |
21,000 |
21,300 |
300 |
1.4% |
3.9 Counts on the A10 at Hay Street and on the A10 South of Ware show an 8% increase in traffic which is similar to the growth observed along the corridor between Ware and the A10/A120 roundabout. As these count sites are more likely to be influenced by other factors than the bypass, it is possible that traffic growth has increased along the A10 in this area for other reasons and therefore the observed traffic growth along the bypassed corridor may not be wholly attributable to the opening of the bypass.
3.10 The counts indicate that traffic on the A1184 which runs parallel to the A10 remained steady, whereas A414 Eastwick Road which links Harlow and Ware has seen a 10% increase in traffic. The count at Dassels Hill shows a decrease in traffic, indicating that the bypass has not encouraged any re-routing of traffic through the villages of Hay Street and Green End to access the A10.
Vehicle Classification
3.11 Based upon the classified data it is possible to determine whether in addition to any changes in traffic flows in the study area, the proportion of HGV's has changed, i.e. whether the number of HGV's have decreased by a greater proportion than the total traffic. For the classified data obtained from the Manual Turning Counts, HGV's have been classed OGV1 and OGV2 combined.
3.12 Table 3.3 shows the percentage of traffic which is HGV. The sites on the A10 and A120 suggest small decreases of approximately 0.5% in HGV's through the corridor between Ware and the A10/A120 roundabout, but the percentage of HGV's through Wadesmill, High Cross and Colliers End has been reduced from between 8%-10% to 4%-5%, indicating that the bypass has clearly been successful in re-routing HGV's out of these villages.
Table 3.3 - Proportion of HGV's through the A10 Corridor
|
Site |
Before |
After |
Change |
|
Old A10 through Wadesmill, High Cross and Colliers End |
|||
|
Old A10 South of Standon Roundabout |
7.8% |
4.1% |
-3.7% |
|
Old A10/Anchor Lane Junction North |
8.7% |
3.7% |
-5.0% |
|
Old A10/Anchor LaneJunction |
9.5% |
4.4% |
-5.1% |
|
A10/A120 | |||
|
A10 Bypass |
N/A |
7.4% |
N/A |
|
A10 North of A10/A120 Roundabout |
8.5% |
7.8% |
-0.7% |
|
A10 Hay Street |
8.7% |
8.2% |
-0.5% |
|
A120 East of A10/A120 |
7.2% |
7.2% |
0% |
Journey Times
3.13 In order to look at changes in journey times, data collected in June 2002, as part of the 'Before' surveys, has been compared to data collected in 2nd November 2004. The 'After' study also included a route carried out using the new bypass.
3.14 A table of results splitting journey time surveys by the 8 designated timing points on the A10 through Wadesmill, High Cross and Colliers End is included in Appendix B.
3.15 Table 3.4 below compares the new A10 route travel times (between the Standon Hill roundabout to the A1170/A10 intersection North of Ware) with the equivalent journey on the old A10 route timed before the A10 bypass was open.
Table 3.4 - Comparative 'Before' and 'After' Journey Times
|
|
|
Route Used |
Route Used |
|
|
Direction |
Period |
Old A10 'Before' |
A10 Bypasss 'After' |
Time saved using bypass |
|
Southbound |
AM |
06:44 |
04:47 |
01:57 |
|
Northbound |
AM |
06:44 |
04:53 |
01:51 |
3.16 The table above highlights a best journey time saving of 6 minutes in the PM peak Southbound, with savings of between 1.5 and 2 minutes for Northbound flows and for AM peak and inter-peak Southbound flows.
3.17 Table 3.5 below compares the journey times on the original A10 route via Wadesmill, High Cross and Colliers End, 'before' and 'after' the bypass was opened.
Table 3.5 - Comparative 'Before' and 'After' Journey Times on the old A10
|
Route Used |
Route Used |
|||
|
Direction |
Period |
Old A10 'Before' |
Old A10 'After' |
Time saved after opening of bypass |
|
Southbound |
AM |
06:44 |
07:49 |
-01:05 |
|
Northbound |
AM |
06:44 |
07:55 |
-01:11 |
3.18 With the exception of PM Peak Southbound flows, journey times have increased along the old A10. These journey time increases will be as a result of speed limit reductions on the old A10. The speed limit through the village centres have been reduced to 30 mph, and the remaining lengths are 40 mph, with the exception of the stretch between High Cross and Colliers End, which is 50 mph.
Journey Speeds
3.19 Table 3.6 compares speeds 'Before' on the A10 through Wadesmill, High Cross and Colliers End and 'After' on the A10 Bypass.
Table 3.6 - Comparative 'Before' and 'After' Journey Speeds
|
Speed on Route Used (KPH) |
Speed on Route Used (KPH) |
|||
|
Direction |
Period |
Old A10 'Before' |
A10 Bypass 'After' |
Speed Difference |
|
Southbound |
AM |
64 |
93 |
29 |
|
Northbound |
AM |
64 |
89 |
25 |
3.20 The journey time surveys show that for vehicles using the A10 bypass, journey speeds have increased between 21 kph and 44 kph, compared with using the old A10 before the construction of the bypass.
Conclusion
4.1 The traffic data collected as part of this Traffic Impact Study has shown that the new A10 Wadesmill, High Cross and Colliers End Bypass, which opened on 8th October 2004, carried around 23,000 vehicles per day (on an average weekday) in November 2004.
4.2 Traffic count data, post scheme opening, shows significantly reduced daily traffic volumes on the bypassed section of the A10 between Ware and the A10/A120 roundabout, clearly indicating that the scheme has been successful in routing approximately 21,000 vehicles away from the old A10, which represents an 80-85% reduction in traffic levels through the three villages.
4.3 Traffic on local roads has also reduced, with the most significant impacts on Anchor Lane and Cold Christmas Lane, which have had reductions in traffic of 1,900 vpd (36%) and 650 vpd (62%) respectively. The decrease on Anchor Lane is assumed to be due to traffic re-routing onto Westmill Road (A602) to join onto the bypass.
4.4 Traffic on the A120 has increased by 2,200 vpd. Evidence from traffic counts strongly suggest that this traffic is due to long distance strategic re-routing since the opening of the scheme.
4.5 The proportion of HGV's of total traffic through the villages has decreased from 8-10% to 4-5% indicating that the bypass has clearly been successful in re-routing HGV's out of these villages.
4.6 Journey time data suggests that time savings of around 2 minutes is being forecast for journeys from the A10/A120 Standon Hill roundabout to the A10/A1170. The exception is for south bound trips in the PM peak where savings of 6 minutes are indicated.
4.7 The One Year 'After' Count for this scheme's Post Opening Project Evaluation (POPE) will be undertaken in November 2005.