For some time I've thought that there is a relatively cheap investment in technology that could be made that would save large amounts of oil, reduce carbon emissions, improve road safety and speed up traffic flow. Few things are as simple as they first sound, so I thought I would post these ideas here to see what others think. There is nothing especially original here and I would expect this to have come up before, so if anyone knows of other references to similar ideas, I would like to read them. The idea is to develop a flexible traffic control system that is expandable in the future as technology improves. Initially this could be used to simply regulate the maximum speed of vehicles on major roads via wireless telemetry to and from short range roadside basestations but, once in place, such a system could be expanded as an aid to navigation and even for information flow for future driverless vehicles. Similar, if slightly less sophisticated systems, are already in place on many roads. TrafficMaster in the UK for example. A system that sends a short message of a maximum speed would be a relatively simple piece of wireless technology and there a number of available frequency bands that could be used to send this short range communication and also a variety of suitable modulation schemes. The data rate is very low, and for this sort of communication the number of basestations in a length of road need not be large. This would not be difficult to implement. What is more difficult is the enforcement that all vehicles would need radio transceivers and speed limiters fitted. This would be met with hostility from many and would be spurred on by the motor industry who would see such a move as destabilising in that it would completely change the current style of marketing in favour smaller engined, lower speed vehicles. The psychology here is important. There is a tendency for people to want to go faster than others and "racing" on public roads can be extremely hazardous. If there is a maximum speed automatically enforced such competitions are impossible. To avoid the possibility of the limiters being adjusted with slight differences in their speed setting, these need to be periodically recalibrated by doppler radar speed measurement and two way telemetry that compares the vehicle's internal speed measurement with that of the external radar based measurement. Extending this concept to very large vehicles would be useful in preventing the five minute overtaking maneouvres that occurs because there may only be a 0.1mph speed difference. Such vehicles already have limiters (in Europe) with a maximum speed of 56mph which means that the drivers of such vehicles feel that they can do such overtakes and feel no personal responsibility for delay to other road users; they believe it is not their fault they can't accelerate a bit more and get past quickly. An intelligent control system could allow a degree of flexibility here and, by allowing a faster vehicle a slight increase in his limited speed or by slowing down the vehicle being overtaken. None of these measures take away personal responsibility though, and if anyone chose to be "awkward" they could do so, but if the system is perceived to be fair this would be a low level problem I think. To make this an attractive scheme, and because of the inherent extra safety, the speed limits could be higher on well equipped roads, both for HGVs and for private vehicles. If carried out on a large scale, I would guess the extra cost on a motor vehicle would be less than £200. The cost of the added infrastructure is harder to estimate because it would depend on the level of expandability that is chosen to be put in. It seems to me that it should not cost too much more than the current cost of enforcement cameras and the waste of police resources in dealing with speeding motorists though. I think that getting the political will to enforce such a system on all vehicles, including vehicles coming from abroad, would be a big problem. This will be especially so as the more powerful representatives of the motor industry would definitely resist such a move. Perhaps a way is to restrict certain roads to only suitably equipped vehicles. If use of these roads were clearly advantageous, it may provide sufficient incentive whilst allowing a degree of phasing in introducing such a scheme. Any comments??