Car-sharing, lift-sharing and ride-sharing

One obvious way to reduce emissions per passenger kilometer basis is to increase the number of passengers in each vehicle. A modern family car with 4 people on board can have lower CO2 emissions per passenger kilometer than a bus, train or coach. Consider: the average new car in the UK emits about 160g/km. Divided by 4, that’s 40g/pkm; not bad when you consider that emissions for train and bus are listed by DEFRA as 60g/pkm and 107g/pkm respectively (the figure for coach is only 29g/pkm).

Trouble is, most car journeys aren’t shared. As car ownership has increased, so car occupancy levels have decreased. In the early 1960s the average was over 2 people per vehicle. Today it’s less than 1.2. Even a 1% improvement in car occupancy levels would be the equivalent of a reduction of over one billion vehicle miles.

Ride-sharing is not new, as the picture above shows. When I was a student in the 1970s hitching from campus to town was an institution, with an orderly queue and a well-understood routine.

ICT can help, though, especially where the routines don’t exist. For example, websites like, which is one of the biggest lift-sharing (or car pooling) websites, allow users to enter details of the journey they wish to make and either look for people offering a lift or offer a lift themselves. There is a nice presentation from Liftshare, which I have made available here.

Some lift-sharing websites use route planning software to predict routes and enable users to offer lifts ‘en-route’ rather than only finding matches based on start and end points of the journey. But the single biggest success factor seems to be to have a large database of users which in turn gives the best chance of finding a good match. Liftshare has a user base over which most commercial social networking sites would drool.

There are lots of ICT-related projects around “dynamic ride sharing” – aimed at facilitating a more flexible model which doesn’t rely on routinised journeys (like commuting to work). The aspiration is “a system that facilitates the ability of drivers and passengers to make one-time ride matches close to their departure time.” There is a rather good wiki site listing the projects and some attempts to define open standards to make it all work.

Mobile devices and GPS abound. There is even a trial scheme running in Brescia in Italy in which users wear hi-tech bracelets with built in breathalysers and use social networking tools to offer and request lifts from friends – have a look at the slightly creepy video. Of course, this is just a trial. As yet there’s little sign that any of these projects are making much of an impact – except in the world of VC finance. It’s possible that some simpler initiatives – a bit of street furniture, like my old hitching point at university – might make more of an impact. Still, the potential is obviously there, and there a few nice side benefits, like building community as well as delivering transportation.

Here’s a more recent overview with some nice updates and even more projects. And a link to a US presentation on Smart Jitneys, which talks about Peak Oil and energy security as well as climate change.

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