Summary
The area around Bourn has limited public transport links. This results in 75% of residents at present relying on the private car for commuting. Local car traffic has increased substantially over the last 10 years resulting in a road infrastructure that is already at capacity. The Highways Agency estimates that a new development of 3,500 houses at Bourn Airfield could result in an additional 29,750 daily trips using SCATP trip rates. [13] The West Cambourne development would add a further 19,125 trips based on the same SCATP rates. With limited scope to increase the capacity of the local road network a new development of this size in the area is unsustainable.
4.2 Rail links
4.2.1 There are no rail links in the Bourn area. As Figure 3 shows, the train line serving Cambridge goes from the north to the south, with no option available to commuters travelling to Cambridge from the west.
Figure 3 - Map of train stations around Cambridge [14]
4.3 Bus links
4.3.1 The villages around Bourn are currently under-served by buses. There are only four bus routes that link the villages in the area to each other and to employment sites around Cambridge. [15] Due to the poor bus service, only 5% of working residents of
Bourn Ward use buses as their main method of transport to work. [16]
4.3.2 None of the four bus services from the area go directly to the major employment sites at Addenbrooke’s Hospital and the Cambridge Science Park. Instead, residents wishing to use bus transport have to take a bus (Citi 4) into the centre of Cambridge
and then transfer onto another route back out to the south for Addenbrooke’s Campus or north for the Science Park; trips to both sites take over an hour as a result.
4.3.3 Three of the routes (1,2 and Citi 4) travel down the A1303 from the junction with the A428 to Queens Road. During rush hour this is one of the local pinch points and makes bus journeys even less attractive to commuters wanting to shorten their travel
time each morning and evening. The bus timetables for these routes show that it takes 40 minutes to complete the journey from Bourn Airfield into Cambridge during rush hour compared with only 20 minutes during the rest of the day. [17]
4.3.4 Department for Transport traffic count studies suggest that subsidised bus routes generally only achieved a 10% reduction in car volumes. [18] New S106 subsidised buses would have a modest impact compared to the huge increase in commuter traffic
which would result from an additional 5,000 dwellings being built along the corridor.
4.3.5 Despite the poor public transport infrastructure in the area, the proposed transport plan for the St Neots and Cambourne to Cambridge corridor relies almost entirely on buses. [19]
4.3.6 In contrast, the new Cambridgeshire Guided Busway connects the Addenbrooke’s and Science Park sites to many other communities in South Cambridgeshire (see Figure 4). This busway (in which the County Council has invested £152 million) gives
access to Addenbrooke’s site from towns and villages north of the city and also from villages south of the city via the Trumpington Park and Ride, which is located at junction 10 of the M11.
The area around Bourn has limited public transport links. This results in 75% of residents at present relying on the private car for commuting. Local car traffic has increased substantially over the last 10 years resulting in a road infrastructure that is already at capacity. The Highways Agency estimates that a new development of 3,500 houses at Bourn Airfield could result in an additional 29,750 daily trips using SCATP trip rates. [13] The West Cambourne development would add a further 19,125 trips based on the same SCATP rates. With limited scope to increase the capacity of the local road network a new development of this size in the area is unsustainable.
4.2 Rail links
4.2.1 There are no rail links in the Bourn area. As Figure 3 shows, the train line serving Cambridge goes from the north to the south, with no option available to commuters travelling to Cambridge from the west.
Figure 3 - Map of train stations around Cambridge [14]
4.3 Bus links
4.3.1 The villages around Bourn are currently under-served by buses. There are only four bus routes that link the villages in the area to each other and to employment sites around Cambridge. [15] Due to the poor bus service, only 5% of working residents of
Bourn Ward use buses as their main method of transport to work. [16]
4.3.2 None of the four bus services from the area go directly to the major employment sites at Addenbrooke’s Hospital and the Cambridge Science Park. Instead, residents wishing to use bus transport have to take a bus (Citi 4) into the centre of Cambridge
and then transfer onto another route back out to the south for Addenbrooke’s Campus or north for the Science Park; trips to both sites take over an hour as a result.
4.3.3 Three of the routes (1,2 and Citi 4) travel down the A1303 from the junction with the A428 to Queens Road. During rush hour this is one of the local pinch points and makes bus journeys even less attractive to commuters wanting to shorten their travel
time each morning and evening. The bus timetables for these routes show that it takes 40 minutes to complete the journey from Bourn Airfield into Cambridge during rush hour compared with only 20 minutes during the rest of the day. [17]
4.3.4 Department for Transport traffic count studies suggest that subsidised bus routes generally only achieved a 10% reduction in car volumes. [18] New S106 subsidised buses would have a modest impact compared to the huge increase in commuter traffic
which would result from an additional 5,000 dwellings being built along the corridor.
4.3.5 Despite the poor public transport infrastructure in the area, the proposed transport plan for the St Neots and Cambourne to Cambridge corridor relies almost entirely on buses. [19]
4.3.6 In contrast, the new Cambridgeshire Guided Busway connects the Addenbrooke’s and Science Park sites to many other communities in South Cambridgeshire (see Figure 4). This busway (in which the County Council has invested £152 million) gives
access to Addenbrooke’s site from towns and villages north of the city and also from villages south of the city via the Trumpington Park and Ride, which is located at junction 10 of the M11.
Figure 4 - Route of the Cambridge Guided Busway [20]
4.4 Current commuting behaviour
4.4.1 The lack of public transport in the area means that residents of the Bourn Ward (covering Bourn and Cambourne) are heavily reliant on private car journeys for commuting.
4.4.2 This is demonstrated by the 2011 census data which shows that 75% of working residents in the Bourn Ward travel to work by car.21 In contrast, only 68% of the working population in South Cambridgeshire as a whole use this method of travel for
commuting.
4.4.3 It is also known that residents of Cambourne travel further to work than residents of other parts of South Cambridgeshire [22] due to the distance to the major employment sites highlighted in the previous section of this document.
4.5 Commuter routes – Bourn Airfield to Addenbrooke’s Hospital
4.5.1 One of the largest employment sites in the Cambridgeshire area is at Addenbrooke’s Hospital to the south of the city.
4.4 Current commuting behaviour
4.4.1 The lack of public transport in the area means that residents of the Bourn Ward (covering Bourn and Cambourne) are heavily reliant on private car journeys for commuting.
4.4.2 This is demonstrated by the 2011 census data which shows that 75% of working residents in the Bourn Ward travel to work by car.21 In contrast, only 68% of the working population in South Cambridgeshire as a whole use this method of travel for
commuting.
4.4.3 It is also known that residents of Cambourne travel further to work than residents of other parts of South Cambridgeshire [22] due to the distance to the major employment sites highlighted in the previous section of this document.
4.5 Commuter routes – Bourn Airfield to Addenbrooke’s Hospital
4.5.1 One of the largest employment sites in the Cambridgeshire area is at Addenbrooke’s Hospital to the south of the city.
Figure 5 - Routes from Bourn Airfield to Addenbrooke’s Hospital/Biomedical campus
4.5.2 The primary route via the A428, A1303 and M11 should take around 20 minutes. However the congestion at the major pinch point on the A1303 at Madingley Hill currently results in a journey some 15 to 20 minutes longer. The proposed mitigation for this in the Transport Strategy is insufficient. The increased traffic in the area as a result of the Bourn Airfield development would exacerbate the delays on Madingley Hill and result in more commuters choosing alternative routes along local roads, through villages - so-called “rat-running”.
4.5.3 The volume of car traffic at Madingley Hill has risen 28% in the last 10 years. [23] Figure 6 shows this increase along with the number of buses over the same period.
4.5.2 The primary route via the A428, A1303 and M11 should take around 20 minutes. However the congestion at the major pinch point on the A1303 at Madingley Hill currently results in a journey some 15 to 20 minutes longer. The proposed mitigation for this in the Transport Strategy is insufficient. The increased traffic in the area as a result of the Bourn Airfield development would exacerbate the delays on Madingley Hill and result in more commuters choosing alternative routes along local roads, through villages - so-called “rat-running”.
4.5.3 The volume of car traffic at Madingley Hill has risen 28% in the last 10 years. [23] Figure 6 shows this increase along with the number of buses over the same period.
Figure 6 - Daily volume of cars and buses on Madingley Hill
4.6 Commuter routes – Bourn Airfield to Science Park and St Neots
4.6.1 The primary trunk route serving the Bourn Airfield site, the A428, is constrained in capacity both west and east of the site. To the west, the route used by London commuters to access the rail station at St Neots, the Highways Agency state "the A428
corridor is seriously limited in capacity between the A1 and A1198. At present there is no realistic prospect of resolving this". [25] To the east, the route used to access the Cambridge Science Park, traffic from the A428 merges with that from the A14 and the
M11 at the Girton Interchange, resulting in serious congestion at peak times.
4.7 Carbon emissions
4.7.1 According to the 2011 census there were 0.998 car commuters per dwelling in the Bourn Ward.26 Based on this figure, an additional 9,978 commuting car journeys (one each to and from place of work) each day will be generated by building 5,000 extra
houses in the area.
4.7.2 Assuming the provision of bus services has a similar effect on car journeys in the corridor as it did when they were provided as part of the Cambourne development (10% reduction), this will equate to an additional 8,184 daily commuting car journeys
in the area.
4.7.3 On average residents of the Bourn Ward work 213 days per year; Cambourne residents travel, on average, 10 km further to work than residents of the rest of South Cambridgeshire. [27] Assuming the residents of the new developments follow a similar
work pattern, the additional commutes mean that there will be 4,260 km travelled each year by each new resident of the Bourn Airfield and West Cambourne developments because the developments are further away from employment centres than the district average.
4.7.4 Assuming the new residents all have cars no older than 5 years (unlikely since many of the houses would be affordable housing) this will lead to an additional and unnecessary carbon footprint of 2,521 tonnes per year.28 Even if the planned bus
improvements achieve a 20% reduction in commuting car journeys, there will still be 1,969 tonnes of carbon emissions generated each year by the extra 20 km residents have to travel to work each day.
4.8 Conclusion
The Bourn Airfield development is badly served by public transport – there are no rail links either existent or feasible, and bus transport will suffer from traffic congestion at a number of known bottlenecks which already cause problems in the area. The vast majority of residents will be forced to use the private car for all travel, both commuting and other, significantly exacerbating existing congestion on both trunk and local routes in the area, many of which are already at or close to capacity.
4.6 Commuter routes – Bourn Airfield to Science Park and St Neots
4.6.1 The primary trunk route serving the Bourn Airfield site, the A428, is constrained in capacity both west and east of the site. To the west, the route used by London commuters to access the rail station at St Neots, the Highways Agency state "the A428
corridor is seriously limited in capacity between the A1 and A1198. At present there is no realistic prospect of resolving this". [25] To the east, the route used to access the Cambridge Science Park, traffic from the A428 merges with that from the A14 and the
M11 at the Girton Interchange, resulting in serious congestion at peak times.
4.7 Carbon emissions
4.7.1 According to the 2011 census there were 0.998 car commuters per dwelling in the Bourn Ward.26 Based on this figure, an additional 9,978 commuting car journeys (one each to and from place of work) each day will be generated by building 5,000 extra
houses in the area.
4.7.2 Assuming the provision of bus services has a similar effect on car journeys in the corridor as it did when they were provided as part of the Cambourne development (10% reduction), this will equate to an additional 8,184 daily commuting car journeys
in the area.
4.7.3 On average residents of the Bourn Ward work 213 days per year; Cambourne residents travel, on average, 10 km further to work than residents of the rest of South Cambridgeshire. [27] Assuming the residents of the new developments follow a similar
work pattern, the additional commutes mean that there will be 4,260 km travelled each year by each new resident of the Bourn Airfield and West Cambourne developments because the developments are further away from employment centres than the district average.
4.7.4 Assuming the new residents all have cars no older than 5 years (unlikely since many of the houses would be affordable housing) this will lead to an additional and unnecessary carbon footprint of 2,521 tonnes per year.28 Even if the planned bus
improvements achieve a 20% reduction in commuting car journeys, there will still be 1,969 tonnes of carbon emissions generated each year by the extra 20 km residents have to travel to work each day.
4.8 Conclusion
The Bourn Airfield development is badly served by public transport – there are no rail links either existent or feasible, and bus transport will suffer from traffic congestion at a number of known bottlenecks which already cause problems in the area. The vast majority of residents will be forced to use the private car for all travel, both commuting and other, significantly exacerbating existing congestion on both trunk and local routes in the area, many of which are already at or close to capacity.
References:
13 http://www.scambs.gov.uk/sites/www.scambs.gov.uk/files/documents/6a.%20SHLAA%202013%20Appendix%207i%2020New%20
Settlements.pdf
14 http://www.theguardian.com/news/datablog/2011/may/19/train-stations-listed-rail#map
15 There is also a school service to Comberton and another two buses between Cambourne and St Neots.
16 Living In Cambourne, Cambridgeshire County Council, 2006
17 http://www.cambridgeshire.gov.uk/transport/around/buses/bus-times.htm
18 Department for Transport, Traffic Counts.dft.gov.uk/traffic-counts
19 Draft Transport Strategy for Cambridge and South Cambridgeshire, 2013
20 http://en.wikipedia.org/wiki/File:Cambridgeshire_guided_busway.png
21 http://ukcensusdata.com/bourn-e05002795
22 Living In Cambourne, Cambridgeshire County Council, 2006
23 Department for Transport, Traffic Counts.dft.gov.uk/traffic-counts
24 Department for Transport, Traffic Counts.dft.gov.uk/traffic-counts
25 SHLAA site assessment for site 010, 6w. SHLAA 2013 Appendix 7i - Caldecote.pdf
26 http://ukcensusdata.com/bourn-e05002795
27 Living In Cambourne, Cambridgeshire County Council, 2006
28 http://www.smmt.co.uk/co2report/
13 http://www.scambs.gov.uk/sites/www.scambs.gov.uk/files/documents/6a.%20SHLAA%202013%20Appendix%207i%2020New%20
Settlements.pdf
14 http://www.theguardian.com/news/datablog/2011/may/19/train-stations-listed-rail#map
15 There is also a school service to Comberton and another two buses between Cambourne and St Neots.
16 Living In Cambourne, Cambridgeshire County Council, 2006
17 http://www.cambridgeshire.gov.uk/transport/around/buses/bus-times.htm
18 Department for Transport, Traffic Counts.dft.gov.uk/traffic-counts
19 Draft Transport Strategy for Cambridge and South Cambridgeshire, 2013
20 http://en.wikipedia.org/wiki/File:Cambridgeshire_guided_busway.png
21 http://ukcensusdata.com/bourn-e05002795
22 Living In Cambourne, Cambridgeshire County Council, 2006
23 Department for Transport, Traffic Counts.dft.gov.uk/traffic-counts
24 Department for Transport, Traffic Counts.dft.gov.uk/traffic-counts
25 SHLAA site assessment for site 010, 6w. SHLAA 2013 Appendix 7i - Caldecote.pdf
26 http://ukcensusdata.com/bourn-e05002795
27 Living In Cambourne, Cambridgeshire County Council, 2006
28 http://www.smmt.co.uk/co2report/