From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.energy
Subject: Re: Computer controlled cars (was re: high-tech highways)
Date: 28 Jul 92 15:48:45 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <1992Jul27.155912.8580@cs.brown.edu> kjb@cs.brown.edu (Ken Basye) writes:
>Gary Coffman writes:
>
>>Yes, airlines are mass transit, and extremely heavily subsidized mass
>>transit at that. A system that is currently losing gobs of money *despite*
>>that monster subsidy. However, just because a bus uses wheels doesn't mean
>>a car can't use them too. And just because a subsidized airplane uses
>>an autopilot doesn't mean a car can't use a similiar system. The aircraft
>>automatic controls form an existance proof for the technology, they don't
>>mean that if cars adapt automatic control they have to also adapt wings
>>and jet engines.
>
>The question remains whether automatic controls for aircraft
>constitute an existence proof of a system which allows significantly
>increased flow of traffic, which was the original claim for automatic
>control of cars.  Are such systems being used to increase flow by
>allowing closer landings and/or takeoffs, or is their use directed
>only at increased safety?  

Both. At a closing speed of 1000 MPH, an aircraft pilot has 3.6 seconds
to see another aircraft, determine it's on a collision course, and
maneuver out of the way under conditions of good visibility (VFR rules).
With poor visibility, the first indication is seeing the other pilot's
look of terror. With an autopilot, the aircraft can be maintained at
the assigned altitude, course, and speed with much greater accuracy
than by a bored pilot. This increases safety at short vertical and
horizontal spacings. Assuming ATC is doing it's job, a big assumption,
then much closer spacings can be assigned under automatic control than
under manual control. This is equivalent to narrower lanes and shorter
following distances in automobiles. Even with no increase in speeds,
that gives more cars per hour. With the millisecond reaction time of
electronic controls, higher speeds also become practical. And in fact,
FAA rules allow closer spacing in positive control areas than in uncontrolled
airspace.

Now this is mixing two systems, autopilot and ATC, but that's exactly 
what is being proposed for automatic cars, both combined into the same
equipment. The big question is not whether autopilot offers more precise
control of the vehicle, it does, the big question is whether on board
sensing of speed and position, coupled with a built in knowledge of the
route, and on board sensing of other vehicles and obstacles in the roadway
are sufficient to serve the function of ATC. The first three are certain.
The last is the only bone of contention. Sensing of other vehicles is
relatively simple, radar, ultrasonic ranging, and active communications
are all workable methods of doing that. Sensing smaller roadway obstructions
is slightly more difficult since they can't offer active communications.
Radar systems exist that track bullets in flight, and that can do terrain
matching. On a less grand scale, ultrasonic backup warning systems on
trucks, buses, and RVs can detect the presense of an obstacle in the path
of these vehicles that is out of the driver's line of sight. 

Systems could be built today with off the shelf technology for use on
controlled access roads. Uncontrolled access, and mixed traffic requires
bringing down the cost of certain remote sensing systems. That's straight
forward engineering though and doesn't require any breakthrus.

Gary