I was sadly informed this morning by Ann Lowson that transportation pioneer Martin Lowson has fallen to a stroke this weekend.

Martin had an amazing career but it was more amazing that he was still actively engaged at age 75. We shared a panel last month in Phoenix at the people-mover conference and continued our vigourous debate on the merits of cars like his on closed guideways compared to robocars.

His career included leading a large team on the Apollo project, and building the world's fastest helicopter, as well as faculty positions at Bristol, and you can read some about it here. For me, his big contribution was to found the ULTra PRT company, the first to commercially deploy a PRT. It runs today at Heathrow, moving people between the terminal and the business parking lot.

PRT was conceived 50 years ago, and many, including Martin and myself, were fascinated by the idea. More recently, as readers know, I decided the PRT vision of personal transportation could be realized on city streets by robocars. It's easier to do it today on dedicated guideway, but the infrastructure costs tell me the future lies off the guideway.

That doesn't diminish the accomplishment of being the first to make it work on the guideway. ULTra uses small cars on rubber tires, not a train on rails. They are guided by a laser rangefinder and are fully automated, with no steering wheel.

Last year I invited Martin in to give a talk to Google's car team, and he got a ride in the car, which he quite enjoyed, even though it didn't convince him that they were the future. But unlike other skeptics, I gave him the deepest respect for his skill and experience. People who can found companies and lead engineering and public acceptance breakthroughs while senior citizens are a very rare thing, and the world will miss him.