No, not snails - they're the things with four wheels already on the roads. Slugs. They are a typically spontaneous American solution to gridlock. Their habitats are those lanes on American commuter freeways reserved for cars carrying three or more people. You can get into work on them more than twice as fast as by crawling along the other lanes, but getting formal car-sharing schemes to work at that hour is rather a strain.
That's where the slugs - named after lead makeweights rather than the molluscs - come in. Commuters who want to get in quickly, but don't want to drive, queue at out-of-town carparks .
Solo drivers come by and call out where they are going, and the first two slugs with the same destination hop in. No money changes hands, but the car can then go in the special lane, and everyone benefits.
"We slugs get to work fast and free," says Ed Ayres, of Washington's Worldwatch Institute. "I've been doing it for eight months and I have never had to wait more than two minutes for a ride."
He says it is a neat example of how to use resources more efficiently by sharing. Certainly it seems better than some of the other dodges used to get into the fast lane. There's a thriving trade in blow-up dolls to stick in the seats to look like occupants. One elderly woman in California (allegedly) kept her late husband strapped into a passenger seat to qualify for a two-person lane. It gave a whole new meaning to arriving dead on time.
o HERE'S another question. What colour are the greens?
At first sight, white. Most of the members of environmental pressure groups in both Britain and the US are Caucasians. They are also largely middle-class and their leadership is middle-aged (and often rather stodgy).
But a survey at the University of Connecticut has discovered that African- Americans and Hispanics have a far greener outlook than whites. This is because they "experience first hand the ill effects of environmental destruction."
That's the point. Everywhere it is the poor - and in the US that usually means racial minorities - who live in the most polluted areas, because the well-off can buy their way out. In the Third World, most of the world's poorest people live on ecologically fragile land, and it is the poor who see their children die in their millions from drinking dirty water and breathing the air of wood and dung cooking fires.
This explodes a fondly held Hampstead socialist creed - originally expounded by that New Labour prototype, Tony Crosland - that only the middle classes care about the environment. But it also poses the question of why the green groups have failed to mobilise all this support. Is it because the poor have less money to give their fundraisers?
o BACK home to join a hush-hush group in darkest Clerkenwell trying to work out what to put in a famous building. I'm really not allowed to tell you anything about it, but the edifice is round, I've criticised it, and it has got to be ready by 31 December 1999. There was just one puzzling thing. The person who rang up to stress the need for secrecy also mentioned that a BBC-TV crew would be there, doing a fly-on-the wall documentary.