# Car Train/Platooning update **URL:** \ **Category:** Great Debates\ **Created:** [November 11, 2009, 1:52am UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135 "2009-11-11T01:52:32Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 11, 2009, 1:52am UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/1 "2009-11-11T01:52:32Z")
We’ve discussed this before but just a quick update on [progress made](http://green.autoblog.com/2009/11/10/project-sartre-uses-road-trains-to-save-fuel-on-the-highway/) > [@](#): > > Sartre is a sort of drafting software that would use wireless controls to group up to 8 cars together into a train … The software uses GPS-based technology to control the distance between cars and keeps them moving at a constant speed, always guided by the lead vehicle. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 11, 2009, 5:18am UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/2 "2009-11-11T05:18:19Z")
Trouble is, Sartre makes no provision for leaving the convoy. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [November 11, 2009, 6:19am UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/3 "2009-11-11T06:19:09Z")
> [@Bryan\_Ekers](#): > > Sartre makes no provision for leaving the convoy. The OP’s link says otherwise: > [@](#): > > As they approach their destinations, drivers take over control of their own vehicles, leave the road train by pulling out to the side, and then continue on their own … ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 11, 2009, 12:45pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/4 "2009-11-11T12:45:55Z")
Huh, I was under the impression there was no exit procedure. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 11, 2009, 1:04pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/5 "2009-11-11T13:04:17Z")
I just don’t understand why they are starting out with passenger vehicles. It seems to me that the natural first roll-out is for commercial long-haul trucking with drivers alternating in the lead. ---
**Author:** ![Grumman](https://avatars.discourse-cdn.com/v4/letter/g/43a26b/32.png) [@Grumman](https://boards.straightdope.com/u/Grumman)\ **Post date:** [November 11, 2009, 1:34pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/6 "2009-11-11T13:34:39Z")
> [@DSeid](#): > > I just don’t understand why they are starting out with passenger vehicles. It seems to me that the natural first roll-out is for commercial long-haul trucking with drivers alternating in the lead. Probably because the current limit on the length of a road train is legal, not technical. There’s not much point letting two trucks with two trailers each operate as a single vehicle if one truck with four trailers could do it just as well. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [November 11, 2009, 1:50pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/7 "2009-11-11T13:50:43Z")
what’s in it for the driver of the lead vehicle? Eg why should they volunteer to be responsible for driving the 6-8 cars behind them? And how does someone in the middle leave if it’s not a dual lane motorway? Also considering the conduct of “professional drivers” here in Australia and the hours and fatigure they are exposed to the last thing I’d want to do is put my life in their hands. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [November 11, 2009, 1:55pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/8 "2009-11-11T13:55:17Z")
> [@Bryan\_Ekers](#): > > Huh, I was under the impression there was no exit procedure. There is no exit procedure: human must make their own exit procedure under Sartre 🙂 ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [November 11, 2009, 4:18pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/9 "2009-11-11T16:18:28Z")
> [@Ludovic](#): > > There is no exit procedure: human must make their own exit procedure under Sartre 🙂 Beaten to it. I was going to say if he was confusing exit with existentialism. As for the car device, it is provably a solution that will have to compete with the coming autonomous vehicles, not sure if the fuel efficiency then will be enough to convince people to give control to other drivers even just temporarily. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 11, 2009, 5:50pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/10 "2009-11-11T17:50:11Z")
> [@GIGObuster](#): > > Beaten to it. I was going to say if he was confusing exit with existentialism. I figured Xema would realize the whoosh sooner or later and I was just waiting for the d’oh! Jokes aside, with the aging population I figure we’ll have more and more cases of old people causing fatal accidents and it’ll be the insurance companies refusing to cover them at any price that’ll be the impetus for automated cars or some hybrid solution as described in the OP’s link. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 11, 2009, 7:24pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/11 "2009-11-11T19:24:26Z")
> [@Grumman](#): > > Probably because the current limit on the length of a road train is legal, not technical. There’s not much point letting two trucks with two trailers each operate as a single vehicle if one truck with four trailers could do it just as well. Can you point me to something about those legal limits? The concept is a higher tech convoy, much how many truckers do it now but able to stay a bit closer to each other and to sleep or relax for prolonged shifts while the lead vehicle driver is fully alert driving for a shortish shift, yet still getiing off at their own destination points and proceeding more locally independently from there. ---
**Author:** ![Grumman](https://avatars.discourse-cdn.com/v4/letter/g/43a26b/32.png) [@Grumman](https://boards.straightdope.com/u/Grumman)\ **Post date:** [November 12, 2009, 9:43am UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/12 "2009-11-12T09:43:23Z")
> [@DSeid](#): > > Can you point me to something about those legal limits? I’m going by [Wikipedia](http://en.wikipedia.org/wiki/Road_train), but it says that trucks in the U.S. are limited to two trailers with a maximum length of 63 feet. If the proponents of the car train focused on doing the same thing with trucks, there’s no guarantee that lawmakers wouldn’t simply treat the two+ trucks as a single vehicle if they’re all under the control of a single driver. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [November 12, 2009, 1:47pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/13 "2009-11-12T13:47:50Z")
So … not only would the lead driver be responsible for his own passengers, but also for passengers in the 8 cars behind him? The insurance company would run screaming down the street. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 12, 2009, 2:37pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/14 "2009-11-12T14:37:22Z")
**Gruman** , 1. The initial roll-out is in Spain (with plans to roll-out over the EU), not the US. 2. They are separate vehicles, each traveling under its own power, and each with its own driver inside. There is no guarantee that lawmakers wouldn’t treat them as trailers but none that they would either. I’d suspect that something like this would only happen in the US _with_ Fed level involvement and likely initial subsidization for early adopters. The legal issues would of course be resolved before that. **NinetyWt** , Most analyses conclude that automated vehicle platooning would substantially increase safety. I suspect that insurance companies would end up providing discounts to those who participated in the program. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 12, 2009, 9:32pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/15 "2009-11-12T21:32:26Z")
One time while hitchhiking, I got picked up by one of those huge trailer trucks carrying 20 brand new cars. I climbed up the side of the cab and opened the door. The guy said, “I don’t have much room up here, why don’t you get into one of the cars out back.” So I did. And he was really into picking people up because he picked up 19 more. We all had our own cars. Then he went 90 miles per hour and we all got speeding tickets. -Stephen Wright ---
**Author:** ![Grumman](https://avatars.discourse-cdn.com/v4/letter/g/43a26b/32.png) [@Grumman](https://boards.straightdope.com/u/Grumman)\ **Post date:** [November 13, 2009, 2:39am UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/16 "2009-11-13T02:39:28Z")
> [@DSeid](#): > > **Gruman** , > > 1. The initial roll-out is in Spain (with plans to roll-out over the EU), not the US. Doesn’t matter. The same sort of laws exist in Europe. > [@](#): > > 1. They are separate vehicles, each traveling under its own power, and each with its own driver inside. There is no guarantee that lawmakers wouldn’t treat them as trailers but none that they would either. I disagree. _Something_ made the lawmakers decide that long road trains needed to be prohibited, and I don’t think that platooning avoids that. And even if each has a “driver”, they aren’t actually controlling the vehicle. Only the front driver is. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 13, 2009, 3:52am UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/17 "2009-11-13T03:52:43Z")
Well then I again ask you to please direct me to what those laws are. As to your other point … you have a conclusion about whether or not the reason for prohibiting multi-trailer trucks applies to platooning without knowing even what the reason for the law is? Just that there must be some reason and that it must also apply, even though platooning avoids having multi-trailer trucks getting on and off at ramps and through streets approaching and departing the highways and could form into smaller units as needed for various potential circumstances. Well no arguing with that. ---
**Author:** ![enipla](https://avatars.discourse-cdn.com/v4/letter/e/54ee81/32.png) [@enipla](https://boards.straightdope.com/u/enipla)\ **Post date:** [November 13, 2009, 11:55pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/18 "2009-11-13T23:55:58Z")
I would never join a road train that does not have a professional driver at the head. Even then. I donno. It’s different than an airplane. Presumably, any idiot driver could join and then ask to leave, and screw up the process or have their car fail or whatever. Not for me. I think that a big problem with this idea is cars merging onto the highway. And passing the road train. Even in Kansas, it’s too long and might cause problems. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [November 14, 2009, 7:34pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/19 "2009-11-14T19:34:02Z")
> [@DSeid](#): > > Most analyses conclude that automated vehicle platooning would substantially increase safety. I suspect that insurance companies would end up providing discounts to those who participated in the program. If I were an insurance company, I would be loath to cover a vehicle as part of a platoon, when I know nothing about the lead driver. I have information about the driver I’m insuring, and I’ve calculated his/her premium based upon that information. Insuring him/her within a platoon would be asking me to cover an unknown driver who has an unknown driving history (unknown to the company). I don’t think I’d do that. **enipla** brings up good points. How would you be sure that the lead driver is qualified? That would concern me as a participant. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [November 14, 2009, 7:53pm UTC](https://boards.straightdope.com/t/car-train-platooning-update/517135/20 "2009-11-14T19:53:25Z")
I found a little bit about the length limit: > [@](#): > > National vehicle size standards apply on what is known as the National Network of highways. The National Network includes: (1) the Interstate Highway System and (2) highways, formerly classified as Primary System routes, capable of safely handling larger commercial motor vehicles, as certified by states to FHWA. The total National Network system is about 200,000 miles. (See table for specific limits.) > > Federal Commercial Vehicle Size Limits on the National Network > > Overall vehicle length > No federal length limit is imposed on most truck tractor-semitrailers operation on the National Network. > > Exception: On the National Network, combination vehicles (truck tractor plus semitrailer or trailer) designed and used specifically to carry automobiles or boats in specially designed racks may not exceed a maximum overall vehicle length of 65 feet, or 75 feet, depending on the type of connection between the tractor and trailer. > > Trailer length > Federal law provides that no state may impose a length limitation of less than 48 feet (or longer if provided for by grandfather rights) on a semitrailer operating in any truck tractor-semitrailer combination on the National Network. (Note: A state may permit longer trailers to operate on its National Network highways.) > > Similarly, federal law provides that no state may impose a length limitation of less than 28 feet on a semitrailer or trailer operating in a truck tractor-semitrailer-trailer (twin-trailer) combination on the National Network. From [FHWA](http://ops.fhwa.dot.gov/freight/sw/overview/index.htm). The U.S. Code seems to be based more on weight than length, although length figures into the formula: > [@](#): > > However, the maximum gross weight to be allowed by any state for vehicles using The Dwight D. Eisenhower System of Interstate and Defense Highways shall be 20,0000 lb carried on one axle, including enforcement tolerances, and a tandem axle weight of 34,000 lb, including enforcement tolerances and with an overall maximum gross weight, including enforcement tolerances, on a group of two or more consecutive axles produced by application of the following formula: > > W = 500[LN/(N – 1) + 12N + 36] > > where W equals overall gross weight on any group of two or more consecutive axles to the nearest 500 lb, L equals distance in feet between the extreme of any group of two or more consecutive axles, and N equals number of axles in group under consideration, except that two consecutive sets of tandem axles may carry a gross load of 34,000 lb each providing the overall distance between the first and last axles of such consecutive sets of tandem axles (1) is 36 ft or more, or (2) in the case of a motor vehicle hauling any tank trailer, dump trailer, or ocean transport container before September 1, 1989, is 30 ft or more: Provided, That such overall gross weight may not exceed 80,000 lb, including all enforcement tolerances, \ and except for those vehicles and loads which cannot be easily dismantled or divided and which have been issued special permits in accordance with applicable state laws, or the corresponding maximum weights permitted for vehicles using the public highways of such state under laws or regulations established by appropriate state authority in effect on July 1, 1956, except in the case of the overall gross weight of any group of two or more consecutive axles on any vehicle (other than a vehicle comprised of a motor vehicle hauling any tank trailer, dump trailer, or ocean transport container on or after September 1, 1989), on the date of enactment of the Federal-Aid Highway Amendments of 1974, whichever is the greater. Source: United States Code, Title 23 - Highways, Chapter 1—Federal-Aid Highways, Subchapter I—General Provisions. Here’s something from [Maine](http://www.mainelegislature.org/legis/statutes/29-A/title29-Asec2390.html): > [@](#): > > B. The maximum overall length of a combination of vehicles may not exceed 65 feet unless otherwise permitted by law. [1999, c. 753, §6 (AMD).] [Next page](https://boards.straightdope.com/t/car-train-platooning-update/517135.md?page=2)