Robot shuttles and buses on demand are being tested to persuade more people to use public transport. Tallinn in Estonia and Luxembourg have even made travel free. The aim is to tackle the impact of one billion cars on the world's roads, which have brought some cities to a virtual standstill. But in order to tempt people away from their cars new incentives are needed. Claire Bates tries out schemes that are being developed across Europe. Presented and produced by Claire Bates