In the French city of Lyon, a privately-run public bicycle network,
V´elo’v, was introduced in 2005 and has proved popular. Lyon’s population
of 470 000 inhabitants is served by 2000 bikes distributed around 175
cycle-stations in an area of 50 km2 (figure 20.15). In the city centre, you’re
usually within 400 metres of a cycle-station. Users join the scheme by paying
a subscription fee of €10 per year and may then hire bicycles free for all
trips lasting less than 30 minutes. For longer hire periods, users pay up to
€1 per hour. Short-term visitors to Lyon can buy one-week subscriptions
for €1.

Other legislative opportunities

Speed limits are a simple knob that could be twiddled. As a rule, cars that
travel slower use less energy (see Chapter A). With practice, drivers can
learn to drive more economically: using the accelerator and brake less and
always driving in the highest possible gear can give a 20% reduction in
fuel consumption.

Another way to reduce fuel consumption is to reduce congestion. Stop-
ping and starting, speeding up and slowing down, is a much less efficient
way to get around than driving smoothly. Idling in stationary traffic is an
especially poor deliverer of miles per gallon!

Congestion occurs when there are too many vehicles on the roads. So
one simple way to reduce congestion is to group travellers into fewer ve-
hicles. A striking way to think about a switch from cars to coaches is to
calculate the road area required by the two modes. Take a trunk road on
the verge of congestion, where the desired speed is 60 mph. The safe dis-
tance from one car to the next at 60 mph is 77 m. If we assume there’s one
car every 80 m and that each car contains 1.6 people, then vacuuming up
40 people into a single coach frees up two kilometres of road!

Congestion can be reduced by providing good alternatives (cycle lanes,
public transport), and by charging road users extra if they contribute to
congestion. In this chapter’s notes I describe a fair and simple method for
handling congestion-charging.

Enhancing cars

Assuming that the developed world’s love-affair with the car is not about
to be broken off, what are the technologies that can deliver significant en-
ergy savings? Savings of 10% or 20% are easy – we’ve already discussed
some ways to achieve them, such as making cars smaller and lighter. Another
option is to switch from petrol to diesel. Diesel engines are more expensive
to make, but they tend to be more fuel-efficient. But are there technologies
that can radically increase the efficiency of the energy-conversion
chain? (Recall that in a standard petrol car, 75% of the energy is turned

Figure 20.15. A V´elo’v station in Lyon.
Figure 20.16. With congestion like this, it’s faster to walk.