The key to getting the economic benefits of reducing congestion is to nudge drivers away from private cars. The best chance of influencing such decisions is when users make other changes. Having facilities available when they move house or start a new job will result in the greatest change.
If this switch is for the whole trip (with walk, cycle, bus and train contributing), there are also economic gains to be made by enabling households to function with fewer cars.
The main alternative for many in villages within six miles of Cambridge who drive, either to work or to a P&R site, is to cycle. For those further out there should be the alternative of cycling to a local ‘hub’ well served by public transport.
Census data (2011) show 8.5% in Sawston cycling to work, yet only 2.7% in Bar Hill, both of which are similar distances from Cambridge. The reason is obvious: no easy cycle routes from Bar Hill.
Regarding distances cycled, census data for South Cambridgeshire show approaching 10% of the 68,000 ‘to work’ trips each day are by cycle with 2,400 cycling trips being more than 5km and over 650 more than 10 km.
In Cambridge where over 17,000 cycle to work each day, (nearly as many as by car or van!) some 1,200 cycle more than 5km and almost inevitably part of those cycle trips will be on South Cambridgeshire cycle routes.
Cycling by residents of necklace villages to or from Cambridge has nearly doubled (89% increase) in the past nine years, with over 10,000 trips now recorded each weekday, hence the 2011 census figures above will be an underestimate. (Cambridgeshire Traffic Monitoring reports).
The Shelford to Addenbrooke’s path, opened in 2006, and well away from busy roads, now has over 1,000 trips per typical weekday, without significant reduction in cycling on adjacent roads.
Cycle routes do need to be of a quality such that those who can cycle, but are not confident in heavy traffic, or on poor surfaces, will cycle five days a week. They need to be usable by a wide range of ages and abilities, on ordinary bikes and in ordinary clothes. Those young people who become independent by cycling to school or college are less likely to become car dependent when they start working.
Congestion reduction should be significant
In the county’s 2013 Cambridge Cordon survey there were about 160,000 car and 10,000 bike trips across the cordon. If we could double the recent increase in cycling trips by transfers from driving, it would reduce car trips by about 10%. This is about the same reduction as occurs in peak-hour car trips on the main radials between a half-term week and a term-time week. We all know how little peak-hour car congestion there is in half-term weeks.
In theory, such a switch would almost eliminate congestion in Cambridge. Of course just as with, say insulating your house, not all such benefits will be achieved. If you insulate your house you will almost certainly keep it at a more comfortable temperature during cold weather, so the saving on energy bills may be less than expected. Similarly, if we reduce traffic on the main radials, such that congestion (especially important for buses) is significantly reduced, more trips will be generated, negating much of the benefits, unless other measures, such as controlling parking, are taken. Even just getting 100 peak-hour drivers into Cambridge out of their cars and onto bikes would reduce the net queue lengths by around half a mile!
Safer routes to schools – and more
Many of the proposed schemes offer much better routes to village colleges. That not only gives the degree of independence mentioned above, but also reduces car traffic and the need for school buses. It also offers opportunities for other utility trips, say for work or shopping. Such routes are especially valuable for small communities, with no shop, pub or local primary school, and on busy rural roads.
What about ‘local hubs’?
The plans propose some local hubs, but we already have a number of rural railway stations which, with much improved cycle routes and parking, would make excellent rural hubs. Proposed improvements in train frequency, and the Science Park station, add significant extra value to such schemes as they remove the need for car trips in the congested areas around Cambridge.
Are existing Cambridge P&R sites not just ‘local hubs’?
There is already congestion on the approaches to many P&R sites and when full this negates much of the value for occasional users. Providing capacity on approaches and for extra parking at P&R sites is expensive. For just the cost of another 500 spaces it should be possible to construct some 4 miles of quality cycle route. Enabling these alternatives frees up car space for those from further away who have fewer choices.
The true economic benefit of such cycle routes will be higher than that in the published assessment, as the DfT EAST (Early Assessment and Sifting Tools) precluded the inclusion of any health benefits. When health benefits are included using ‘Health Economic Assessment Tools’, the benefits from such routes are likely to at least double.