# Light Rail Systems **URL:** \ **Category:** Factual Questions\ **Created:** [September 7, 2016, 5:24pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279 "2016-09-07T17:24:10Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [September 7, 2016, 5:24pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/1 "2016-09-07T17:24:10Z")
Salt Lake City has a nice light rail system that runs along the normal roads. It seemed odd to me that the trains stopped for stop lights like the regular traffic. Is that standard? I thought in Seattle their system stopped traffic for trains. The Salt Lake system was built in 2002 for the Olympics and it goes outside SLC as well. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [September 7, 2016, 5:26pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/2 "2016-09-07T17:26:30Z")
Light rail doesn’t always have the luxury of unrestricted routing. When Sacramento added it in the 1980s and extended it in the 2000s, the existing freeway system was spaciously enough laid out that lines could be run in the wide medians. A lot of what runs downtown shares road space with cars, though, and it can be confusing/scary to have a train blow by you at 40MPH while you wait to turn across those tracks. The signals are not always entirely clear, especially to new and visiting drivers. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [September 7, 2016, 5:34pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/3 "2016-09-07T17:34:20Z")
The Green Line in Boston (a subway trolley that that runs as a light rail system when above ground) stops for traffic lights. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [September 7, 2016, 5:37pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/4 "2016-09-07T17:37:32Z")
Calgary and Minneapolis, to name two cities off the top of my head - the tram runs in a private right of way mostly, but sometimes on a road. IIRC traffic is not allowed alongside the LRT, and the crossing arms come down when the train approaches intersections, so it does not stop typically. This can be disruptive - I have heard rumblings that Calgary wants to bury the downtown street section of its LRT. Actual streetcars - Toronto’s, for example - follow the traffic flow, stop at lights , cars use the same lane, etc. (Amsterdam and Rome too, I think I recall). Don’t recall Jerusalem or Istanbul for sure, but I seem to recall they don’t stop, you get the flashing crossing warnings and no traffic within the tracks. Jerusalem it runs down the middle of a major pedestrian-only street for a ways with no obstruction. In Amsterdam, I recall one street so narrow there was only room for one set of rails, so the oncoming trams had to wait for the other direction to finish going through that block. Rome had curbs to keep cars off the center right-of-way in some places, but I remember seeing some guy lifting his handlebars to get his scooter into the uncrowded right-of-way. It depends what the goal is; LRT’s typically have longer between stops than streetcars, which operate more like busses. So LRT is trying to be fast, and not having to stop for lights adds to that - and also makes a case for people to leave the car at home and skip the line. ---
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [September 7, 2016, 5:39pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/5 "2016-09-07T17:39:27Z")
If it stops for stop lights, it’s really like a bus, it just holds more people . And it has less stops than a bus. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [September 7, 2016, 5:41pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/6 "2016-09-07T17:41:36Z")
In Portland, there are dedicated transit lanes in the downtown area. Cars are forbidden to drive in them, and the transit traffic signals work independently of the adjoining car traffic lights. On common streets, transit vehicles stop for traffic lights, but the light rail has its own independent corridors once out of the city center, with automated lights and barricades to stop car traffic where it crosses streets. ---
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [September 7, 2016, 5:44pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/7 "2016-09-07T17:44:38Z")
I did not ride the train outside of SLC so the system may have dedicated lanes there. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 7, 2016, 5:57pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/8 "2016-09-07T17:57:44Z")
In Cleveland, we have about two light rail lines, which at some points of their route run down the middle of automobile streets, and have to stop at the same lights. We also have a bus line that is treated as though it were light rail, and which has its own (in principle, but cars often swerve into them) dedicated lanes, as well as its own dedicated traffic signals (I’m not sure how letting the buses go when the cars next to it can’t helps anything, but apparently some civil engineer thought so). ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [September 7, 2016, 6:09pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/9 "2016-09-07T18:09:17Z")
In Paris their light rail system seems to have preferential control of the traffic lights, giving them most of the time a green light at the expense of auto traffic. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [September 7, 2016, 11:05pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/10 "2016-09-07T23:05:41Z")
I have lived in and visited many cities with various kinds of trolley/light rail lines and some have dedicated rights of way (the Philadelphia Suburban lines, including the Norristown line), some have dedicated ROW over part of their system and run in traffic elsewhere (the subway surface lines in Philly and Boston and the Forchbahn in Zurich), and some are just street running but cars are generally not allowed to ride on the tracks (Philly, Zurich). There are no general rules, just special situations. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 7, 2016, 11:21pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/11 "2016-09-07T23:21:29Z")
In San Jose, the light rail mostly has dedicated lanes; sometimes in the median and sometimes to one side (like when going down a one-way street). In some cases, the rails are shared with pedestrian areas. But it doesn’t have dedicated routes, and so follows the same traffic signals as the roads they travel alongside. I think they must have some sort of prioritization over car traffic, though. Most intersections also have signs warning that a train is coming, but this is just so as not to surprise car traffic. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [September 8, 2016, 1:30am UTC](https://boards.straightdope.com/t/light-rail-systems/765279/12 "2016-09-08T01:30:12Z")
> [@Bijou\_Drains](#): > > I thought in Seattle their system stopped traffic for trains. Of our extant light rail system, only one portion runs along a street at-grade, along MLK in south Seattle. It has its own center lane, but it does cross the perpendicular streets at-grade. If everything is working correctly, the lights are timed such that the cars stop for the train, not the other way around. However, the trains are manned, and can stop at intersections if something has gone awry. The rest of the system is underground or elevated, and the vast majority of the system, once built out, will be grade-separated as well. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [September 8, 2016, 2:01am UTC](https://boards.straightdope.com/t/light-rail-systems/765279/13 "2016-09-08T02:01:02Z")
The Twin Cities just finished a light rail system that connects Minneapolis & St. Paul; it runs mostly down the middle of the main road between them (University Avenue). They closed off every other crossing street so there are fewer intersections, but they still stop for lights. As a result, it isn’t any faster than a bus. They spent a billion dollars on it and could have just put in an electric streetcar system like San Francisco has for a quarter of the cost. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [September 8, 2016, 3:26am UTC](https://boards.straightdope.com/t/light-rail-systems/765279/14 "2016-09-08T03:26:04Z")
> [@Dr.Strangelove](#): > > In San Jose, the light rail mostly has dedicated lanes; sometimes in the median and sometimes to one side (like when going down a one-way street). In some cases, the rails are shared with pedestrian areas. But it doesn’t have dedicated routes, and so follows the same traffic signals as the roads they travel alongside. I think they must have some sort of prioritization over car traffic, though. Most intersections also have signs warning that a train is coming, but this is just so as not to surprise car traffic. The only priority on lights that VTA has is left turn lights. If a train is waiting for the green the left turn light is skipped. ---
**Author:** ![Mr\_Downtown](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)\ **Post date:** [September 8, 2016, 3:53am UTC](https://boards.straightdope.com/t/light-rail-systems/765279/15 "2016-09-08T03:53:54Z")
Signal preëmption is preferred by planners of new light rail systems to speed up service, but they don’t always win the battle with state or local traffic engineers concerned about how preëmption affects overall signal timing, particularly in downtown areas where the signals are part of a coördinated network. Baltimore’s LRT initially had signal preëmption, but it caused such problems that it was discontinued. A lesser alternative that doesn’t disrupt nearby traffic so much is signal _priority,_ in which signals about to change are changed a few seconds early or late to accommodate trains moving through. ---
**Author:** ![SciFiSam](https://avatars.discourse-cdn.com/v4/letter/s/47e85d/32.png) [@SciFiSam](https://boards.straightdope.com/u/SciFiSam)\ **Post date:** [September 8, 2016, 9:39am UTC](https://boards.straightdope.com/t/light-rail-systems/765279/16 "2016-09-08T09:39:49Z")
The Docklands Light Railway in London looks more like a traditional railway, with platforms and stations not on the road, so doesn’t have any traffic lights. In Brussels the light rail system does travel partly by road (and also goes underground on non-road tracks) but never seems to stop for traffic lights. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [September 8, 2016, 10:54am UTC](https://boards.straightdope.com/t/light-rail-systems/765279/17 "2016-09-08T10:54:43Z")
The Manchester (UK) tramway runs partly on separate tracks, partly on public roads and also through pedestrian only areas. Where traffic and trams intersect, trams have priority but they do have to stop sometimes.They win over trolleys because they carry a lot more passengers and get held up a lot less. Out of the town centre, they are quite fast and they are very popular. ---
**Author:** ![PatrickLondon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/patricklondon/32/4422_2.png) [@PatrickLondon](https://boards.straightdope.com/u/PatrickLondon)\ **Post date:** [September 8, 2016, 11:54am UTC](https://boards.straightdope.com/t/light-rail-systems/765279/18 "2016-09-08T11:54:46Z")
Several UK cities have developed modern trams that connect up suburban rail lines that used to run into central terminal stations, by running at street level through city centres and then out the other side, as it were: not just Manchester, but also Sheffield, Nottingham and Croydon/south London. AFAIK when on the roads they have traffic lights at junctions. Likewise one or two Amsterdam tram lines turn into light railways on separate tracks once out of the city centre. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [September 8, 2016, 12:29pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/19 "2016-09-08T12:29:46Z")
> [@Mr\_Downtown](#): > > Signal preëmption is preferred by planners of new light rail systems to speed up service, but they don’t always win the battle with state or local traffic engineers concerned about how preëmption affects overall signal timing, particularly in downtown areas where the signals are part of a coördinated network. Baltimore’s LRT initially had signal preëmption, but it caused such problems that it was discontinued. A lesser alternative that doesn’t disrupt nearby traffic so much is signal _priority,_ in which signals about to change are changed a few seconds early or late to accommodate trains moving through. I have to comment that your use of “ë”, though not formally wrong, certainly is odd looking in this day and age. Language changes and it seems this usage has fallen far enough out of favor that it looks positively archaic, at least to me. I’m not trying to bust your chops; I’m just commenting on me being surprised at how odd it looks despite the fact it was completely ordinary, albeit high register, usage when I was a kid. ---
**Author:** ![Baron\_Greenback](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/baron_greenback/32/48_2.png) [@Baron\_Greenback](https://boards.straightdope.com/u/Baron_Greenback)\ **Post date:** [September 8, 2016, 12:36pm UTC](https://boards.straightdope.com/t/light-rail-systems/765279/20 "2016-09-08T12:36:02Z")
> [@LSLGuy](#): > > Language changes and it seems this usage has fallen far enough out of favor that it looks positively archaic, at least to me. The New Yorker magazine style guide still mandates diæreses. [Next page](https://boards.straightdope.com/t/light-rail-systems/765279.md?page=2)