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Lauri Kangas
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I find this discussion highly interesting in relation to at least two topics. The first is the role of different lines in a larger urban system for serving various trip lengths. I haven't noticed much in depth coverage of this in Jarrett's (excellent) writing although it does feature occasionally. If I understand correctly MAX (and most other US light rail systems) is geared towards long regional trips (rapid transit) while the Portland frequent bus network is geared towards serving a contiguous urban structure. I'm under the impression that the latter is the core market for frequent grid networks. In any case these are somewhat different roles in an overall system and thus direct comparison of statistics does have issues in my opinion. More generally I've been wondering whether a more general typology of public transport network roles could be developed. A perfect typology is almost certainly impossible, but at least having some kind of a shared vocabulary for these roles would make discussions easier and enable better comparisons between groups of lines. Actually I suspect that German speaking Central Europe might have a typology already and we are missing out due to a language barrier. Regarding this topic I've also been quite interested in drawing parallels between public transport roles and the Urban Fabrics spatial models by Leo Kosonen and Peter Newman: http://www.urbanfabrics.fi/uploads/20131024UFKosonen.pdf . They claim that the "inner transit city" fabric tends to extend up to about 8 km (5 miles) from city centres while "outer transit city" fabric can be formed locally around rapid transit nodes. These would seem to match nicely with the typical extent of continuous frequent (grid) networks and longer distance rapid transit systems respectively. Urban Fabrics also suggests an "inner walking city" of only about 1 km radius, but with potential for an "outer walking city" to extend to 2-5 km depending on walkability, bikeability and public transport support. Supporting the walking city seems to match many streetcar/tram systems, but importantly not all of them. Many successful modern tram systems in Central Europe are more at the scale of the "inner transit city" / frequent network. I suspect this difference is a key question for advancing the "urbanism vs. speed" debate. My second topic is a bit more trivial. Here in Helsinki some of the above arguments in relation to modes are turned upside down. We have what I call a legacy tram system extending only about 5 km (3 miles) from the centre. It is quite slow and trips are short, but still highly popular. So popular that costs per boarding are 45 % less than for buses, while costs per passenger-km are 76 % higher. This is of course an unfair comparison because of different roles, but still used with exactly the opposite arguments than above. The most common line here is that the tram system is highly expensive because of high costs in relation to trip length. Cost per passenger-km is commonly used as the main efficiency metric. My standard reply is that while our current tram system obviously has issues, it is quite hard to compare lines or systems that serve wholly different purposes in the system. You can still gain insight from the figures though. This would seem to apply to the above discussion as well.
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Max will hopefully correct me if im wrong, but I believe Zürich has taken things a step further and operates with multiples of 7.5 minutes. The thinking is that 7.5 minutes for the whole day is a "full service", which allows spontaneous travel (freedom). 15 minutes is a "half service", which still offers frequent service for lighter loads and facilitates splitting a line. Key bus, trolleybus and tram routes all operate at 7.5 minutes. 30 minutes and 60 minutes are used for regional routes. These include the regional trains with timed connections with each other and feeder buses at regional hubs. Vehicle size and network design are used to keep the frequency at the desired level. There is a wide range of street running vehicles from short buses to long trams. In really central areas 7.5 minute services will be overlaid for capacity. On the other hand too many overlapping services are avoided where possible so that the traffic light priority system can works as well as possible. A consultant from Bern I talked to considered this 7.5 minutes real freedom. According to him travel increases significantly when a network at this frequency allows spontaneous travel from early till late. I'm sure that expectations vary in different places and for different kinds of trips. Trip length has already been mentioned and is almost certainly a significant factor. Reliability is another one.
Toggle Commented Jan 2, 2012 on how frequent is freedom? at Human Transit
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In the Helsinki region we usually use a rough multiplier of 1.3 for converting air distance to real walking distance. Rounding to the nearest 50 m you get 300/400, 400/500, 500/650 and 600/800. This tends to work quite well in environments without large barriers like motorways or rivers. For walking speed I use 1.2 m/s as this is used in our journey planner and for traffic light engineering. 5.5, 7, 9 and 11 minutes respectively for the above distances. Our new service quality standards include recommended and maximum walking distances to normal or trunk services for each service category in addition to service frequencies. Trunk lines are allowed longer walking distances.
Toggle Commented Apr 27, 2011 on basics: walking distance to transit at Human Transit
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@Ron It may be that several levels of rail services are not financially feasible, but I'm not sure about this. Stations for underground rapid transit tend to be extremely expensive. This is especially the case for deep bore. Might it be possible in given cases to build less stations and use the money to add surface rail as well? If you only have rapid rail, you will often end up adding more stations than is really necessary for fast trips. If costs for surface rail could be kept under control, these might actually cover the costs. Where I come from we can build 2 to 5 km of surface rail for the cost of one underground station. If we can for example take the station spacing from 1 km to 2 km for the undeground, this will cover the costs of the surface rail. This is a bit extreme though, but a believe that in certain cases the equation can work and actually optimize both systems. Especially if you can set up the rapid and surface systems to complement each other for connectivity as well. As examples of such dual solutions from Europe I would offer Prague (http://www.dpp.cz/download-file/3136/Metro+tram_den_new20100307optimal.pdf) and Warsaw (http://beta.um.warszawa.pl/sites/default/files/attach/aktualnosci/Zdazysz_transport_szynowy_mapa.pdf). Note that Warsaw only has one rapid metro line and some local rail built so far although the trams are quite fast there too.
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"Transit designed for short trips is competing with walking and cycling. Transit designed for longer trips within an urban region is competing with freeways." Sounds rather extremist to me. French trams run at around 18 - 25 km/h. Try walking that fast. You'll have trouble even cycling that fast in urban environments. Of course bike trips have the advantage of being door to door, so there is clear overlap with biking, but fast biking is not for everyone. Are we going to leave large amounts of people to the car because in theory they could be cycling if they are fit and willing? Competing with freeways is also a tricky notion. It is often impossible to be faster than a non-stop mostly freeway trip. Why concentrate on a part of the market where it is really hard or impossible to beat the car? I find this analogous to city centres trying to compete with out of town developments by building lots of parking. It is fighting a losing game by definition. I'm not saying speed does not matter. The speed for the whole trip including connections and frequency is generally the most important single factor. But there are many other factors which are significant when combined and should not be ignored. There is also a whole range of speed options available for different purposes. Goals related to sustainable communities are also significant, but very tricky. I agree with Patrick Condon in that we should not promote long trips in theory, but I'm also aware that we are in competition with cars, which will always be worse in this respect. As I come from an European perspective there is another area I would like to highlight: Local and regional railways are abundant in Europe. They usually cater for fast regional trips and usually provide acceptable frequency thoughout the day (unlike US commuter rail). Many of the French and German cities that seemingly only have light rail / trams actually have extensive local rail as well. This means that they have two rail systems catering for two different segments: Fast regional trips and medium to slow speed urban area trips. This is one major reason why surface trams can be attractive as the long trips are already catered for. This leaves flexibility for designing tramways partially as urban improvement projects. Even with this flexibility new tram systems in Europe are not as slow as US streetcars. The 18 - 25 km/h I quoted above is typical. Not competing with walking is a big reason for this. French trams always run in dedicated lanes and usually have full signal priority so they are reliable as well. Taking city space from cars and returning it to soft modes is a key design factor. Tram streets are usually very walkable so it is easy to reach a stop even if stops are about 500 metres apart. So what you really need is two different systems or lines. Because you probably can't affort both at the same time, I think the question comes down to which one you should start with. Trying to serve both purposes with one line is occasionally a possibility, but runs a real risk of a compromise which doesn't serve either purpose very well.
Toggle Commented Apr 23, 2010 on is speed obsolete? at Human Transit
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In theory you can calculate optimal stop spacing, but you need to have usable values for things like the typical distance travelled on the vehicle, cruising speed, stop dwell time and length of connecting walks. Researching these in detail for each route would be hard, but a reasonable set of assumptions can be used to get a rough understanding. I typed up one formula here: http://preview.tinyurl.com/ye6qxue
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Mar 24, 2010