Posts Tagged ‘dedicated transit lane’

h1

Dedicated transit lanes on Austin’s Drag must be designed for light rail

29 September 2015
Busy section of Austin's Drag, Guadalupe St. at W. 24th St. Official city planning by CTR has proposed curbside transit lanes, with buses running on outside lanes as seen in this photo. (Screenshot from Google Streetview.)

Busy section of Austin’s Drag, Guadalupe St. at W. 24th St. Official city planning by CTR has proposed curbside transit lanes, with buses running on outside lanes as seen in this photo. (Screenshot from Google Streetview.)

By Lyndon Henry

The following commentary has been adapted and expanded from remarks posted to an online Austin rail discussion. Lyndon Henry is a transportation planning consultant, a technical consultant to the Light Rail Now Project, an online columnist for Railway Age magazine, and a contributing editor to Austin Rail Now. He is also a member of the Light Rail Technical Forum and Streetcar Subcommittee of the American Public Transportation Association (APTA). His comments highlight the vision of Austin Rail Now and other transit advocates that light rail is justified in, and needs to be planned for, a number of the Austin area’s major travel corridors.

As most Austinites are undoubtedly aware, the Drag is that section of Guadalupe St. stretching between (approximately) West MLK Jr. Blvd. and W. 27th St. Straddled by the University of Texas campus on its east side and the high-density West Campus neighborhood on its west side, the Drag is perhaps the single most important segment of the Guadalupe-Lamar corridor. See: «Long saga of Guadalupe-Lamar light rail planning told in maps» and «Dobbs: Density, travel corridor density, and implications for Guadalupe-Lamar urban rail».


Map shows the Drag area (Guadalupe St., running north-south in center). UT campus lies on the east, West Campus neighborhood on the west. (Screenshot from Google Maps.)

Map shows the Drag area (Guadalupe St., running north-south in center). UT campus lies on the east, West Campus neighborhood on the west. (Screenshot from Google Maps.)


Now, driven partly by their fixation to substitute buses for rail as “rapid transit”, and partly by pressure from some community groups and activists, local civic leaders and official planners are floating plans for dedicated transit (read “bus”) lanes on the Drag. (Official planning defines “the Drag” as continuing north to W. 29th St.)

Last month (August 2015), AURA (originally Austinites for Urban Rail Action), a grouping of mostly Millennial-aged urban planning enthusiasts, posted a proposal for major improvements on the Drag, one of which suggested: “Extend transit priority lanes from Downtown to the Drag”.

At peak periods, transit moves roughly half of the people passing through the corridor. This is to be expected in a central location like the Drag, as transit is by far the most efficient way to move people in a city.

Given the anticipated growth of the city, increasing the throughput of people in the corridor is of paramount importance. The city should plan ahead for increased frequency of existing bus routes, and continue to examine the viability of Guadalupe as a future corridor for rail service. Buses should not have their effectiveness limited by less efficient forms of mobility. Two lanes of Guadalupe should be dedicated solely to transit.

Back in May, per its contract with the City of Austin (COA), UT’s Center for Transportation Research (CTR) produced for city staff a memo of its findings with respect to installing dedicated lanes on the Drag. As summarized by AURA’s John Laycock, the report “modeled three scenarios: Scenario 0) the baseline scenario, Scenario 1) a transit lane in each direction on Guadalupe, and Scenario 2) diverting the buses completely off of Guadalupe onto San Antonio.” Laycock reports that the city subsequently requested CTR to model an additional case, involving one transit lane northbound on Guadalupe and another southbound on Nueces/San Antonio. Results from that additional modeling effort apparently have not yet been released publicly.


Diagram from CTR report for curbside dedicated lanes on the Drag. (Screenshot from CTR memo.)

Diagram from CTR report for curbside dedicated lanes on the Drag. (Screenshot from CTR memo.)


The proposal for dedicated transit lanes on the Drag may seem fairly benign, helpful to public transport and innocuous to the prospects for light rail (LRT). However, installing reserved transit lanes without broader planning for rail can raise some quite serious problems. Depending on their design and implementation, transit lanes could significantly improve or seriously impede the prospects for light rail transit (LRT) — by far, the most feasible and affordable rail option — in the Guadalupe-Lamar corridor. (See «Plan for galvanizing Austin’s public transport development: Light rail starter line in Guadalupe-Lamar».)

First, I’ll note that implementing a high-quality bus service as a precursor to rail can be an effective way of building ridership and preparing the public for the coming rail upgrade. Likewise, establishing reserved transit lanes that can be dedicated to rail can also be helpful. However, both infrastructure and configuration of dedicated transit lanes, done improperly, can create problems.

Infrastructure — Proponents of dedicated transit lanes have argued that all that’s needed is to paint some stripes on the street. And certainly, in the scheme of transit capital projects, just “painting” markings on pavement is relatively cheap. But there’s almost always more involved. The Guadalupe-Lavaca transit lanes, for example, included repaving, plus bus stop relocation and upgrading. Parking meters were removed. And the project has resulted in effectively eliminating the possibility of dedicated LRT tracks on those sides of these streets (bus traffic too heavy).


Buses use curbside reserved lanes on one-way Lavaca St. downtown. Curbside lanes on the Drag would be similar, but on two-way street. Photo: L. Henry.

Buses use curbside reserved lanes on one-way Lavaca St. downtown. Curbside lanes on the Drag would be similar, but on two-way street. Photo: L. Henry.


In previous discussions I’ve suggested that LRT dedicated lanes would need to be relocated on the opposite side of each street. Total cost of the downtown bus lane project was about $370,000 — not a billion-dollar investment, but enough of an investment certainly to give pause to totally redoing this project, or making substantial modifications to it (although modification to add LRT would definitely be a highly worthwhile investment).

We also don’t know what COA and Capital Metro have in mind for the Drag project. Some community transit activists might be thinking very minimalist, but what are official planners thinking?

Configuration — The precise alignment on the transit lanes also needs serious consideration with respect to the needs of LRT (and evidence suggests that a substantial portion of the Austin community would like to see LRT as a project on the planning table now). Curbside lanes — as assumed in the CTR design, described above — are used by several major LRT systems (Portland, Houston, Dallas, and Denver come immediately to mind), but this configuration can often encounter serious problems, mainly with motor vehicle right-turns and especially pedestrian traffic (including where the right turns are made). Another problem for the Drag is the number of driveway cuts and the issue of access to businesses along this commercial alignment.


Denver: Passengers waiting to board LRT train running in curbside lane on Stout St. Photo: Peter Ehrlich.

Denver: Passengers waiting to board LRT train running in curbside lane on Stout St. Photo: Peter Ehrlich.


To be sure, a number of different LRT alignment and configuration options are possible. My preferred alignment concept for the Drag has been to keep both LRT tracks on Guadalupe, in the center (with stations also in the center), and the outside (curb) lanes continued for mixed motor vehicle traffic, including buses. The main reason for this configuration is that buses need access to right-side loading at stops, and I envisioned that local routes like #1 would need to be continued. Of course, bus routes could be moved further west, probably to San Antonio-Nueces, but keeping them on Guadalupe would facilitate relatively easy transfers to and from LRT and bus.

Ideally, the main Drag segment in this heavy-pedestrian/heavy-transit traffic area should be converted to a pedestrian-transit mall, with general motor vehicle traffic prohibited (except perhaps in the case of service vehicles for adjacent businesses). However, a design with reserved transit lanes plus a single mixed-traffic lane in each direction would appear to be possible.

To sum up: While dedicated transit lanes, with very minimal investment, could possibly be helpful as a preparation for LRT, I’d recommend huge caution and vigilance as this notion moves forward. Keeping particularly in mind the considerations I’ve raised above.

In this regard, it’s important to realize that a major chunk of Austin’s civic leadership, and planning establishment, still regard MetroRapid as the city’s “rapid transit system”. Likewise, the fantasy persists that Austin could “become the best bus system we can be” without a rail system. (Cities with the “best bus systems” also seem to happen to have excellent rail systems too.) Reserved transit lanes on the Drag could advance the case for LRT, but only if they’re properly configured, designed, and planned in the context of an ultimate LRT outcome. ■

Advertisements
h1

San Francisco’s N-Judah Muni Metro line shows design option for light rail in Austin’s Guadalupe-Lamar corridor

9 December 2014
N-Judah Line Muni Metro light rail transit (LRT) train running in raised median on San Francisco's Judah St. Alignment in this constricted 80-foot-wide arterial includes space for 2 dedicated light rail tracks, 4 vehicle lanes, and shared sidewalk for pedestrians and bicyclists. Similar alignment design could fit dedicated LRT tracks, 4 traffic lanes, and sidewalks into Austin's Guadalupe-Lamar corridor. Photo (copyright) Eric Haas.

N-Judah Line Muni Metro light rail transit (LRT) train running in raised median on San Francisco’s Judah St. Alignment in this constricted 80-foot-wide arterial includes space for 2 dedicated light rail tracks, 4 vehicle lanes, and shared sidewalk for pedestrians and bicyclists. Similar alignment design could fit dedicated LRT tracks, 4 traffic lanes, and sidewalks into Austin’s Guadalupe-Lamar corridor. Photo (copyright) Eric Haas.

In recent years, critics of installing “urban rail” — i.e., a light rail transit (LRT) line — in the Guadalupe-Lamar (G-L) corridor have endeavored to portray this potential project as an impossibly daunting task, contrary to many years of local planning to do just that. The predominant contention is that these two busy major arterials are simply too narrow to accommodate a double-track LRT alignment on dedicated lanes while maintaining adequate general traffic flow, and that introducing LRT would require either heavy civil works construction, or extensive, costly acquisition of adjacent property to widen the right-of-way (ROW), or both.

However, the G-L travel corridor — most central in the city — actually carries the heaviest travel flow of local arterials, serves the highest-density neighborhoods; and connects the most important activity clusters; thus, ultimately, given the inherent constraints of motor vehicle transportation, some type of high-quality, high-capacity public transport alternative is essential to maintain long-term mobility. Fortunately, there are LRT alignment designs that would facilitate fitting affordable, cost-effective, surface LRT into these arterials, while maintaining at least four lanes of general traffic capacity through most of the corridor.

While this corridor is characterized by an unusually narrow roadway structure — much of both North Lamar Blvd. and Guadalupe St. have total ROW (including sidewalks and curbs) just 80 feet wide — there appears to be adequate ROW width to install dedicated LRT lanes, within a 24-foot reservation, without additional ROW acquisition (easements), together with four traffic lanes (two 10-ft lanes per direction) for most of the alignment, plus sidewalks and curbs (8 fteet) on each side.


North Lamar traffic (several blocks north of the Triangle). Guadalupe-Lamar travel corridor carries heaviest traffic flow of any local Central Austin arterial, serves residential concentration ranking among highest density in Texas, serves 31% of all Austin jobs — yet corridor was "dismembered" by Project Connect and excluded from "Central Corridor" study! Photo: L. Henry.

North Lamar Blvd. has unusually narrow right-of-way width for heavily traveled central local arterial street. Conditions of Guadalupe St. are similar. Photo: L. Henry.


For stations, relatively short segments of additional ROW would need to be acquired — approximately 20 feet of width for 300 feet (about one block) on each side of major intersections intended as station sites. Acquiring wider ROW would also be useful along sections of Guadalupe St. (particularly where the proposed LRT alignment runs adjacent to stretches of state-owned land). Within the Drag section of Guadalupe (W. 29th St. to MLK Blvd.), dedicated LRT lanes could remain in the center of the arterial, with some reconfiguration of traffic lanes and other facilities.

ROW constraints will impact the traction electrification system (TES) and overhead contact system (OCS) design in the G-L corridor. (OCS is the commonly used term for the overhead power wire system; it can be catenary or a simple, single-trolley-wire design.)

Appropriate design of the TES is critical to the narrow overall alignment design required in this corridor. Unlike many other modern new-start LRT installations, for OCS power wire suspension this alignment design would eschew TES center poles (masts) with bracket arms. Instead, to facilitate adequately narrow LRT ROW, this design would use an alternative design whereby the OCS would be carried by cross-span cables suspended from side poles inserted at curbside. Examples of this type of OCS suspension can be found in other LRT installations, such as in Houston, San Diego, and San Jose. (Whether OCS is simple trolley wire or catenary-type suspension would not affect this aspect of alignment design.)

The following schematic diagram illustrates a cross-section of this design for the majority of both North Lamar and Guadalupe, with LRT running in a dedicated reservation, two traffic lanes on each side, and sidewalks shared by pedestrians and bicyclists on each side.


Cross-sectional diagram of major arterials in corridor, showing center LRT reservation, traffic lanes, sidwalks, and side-mounted TES poles for suspending the OCS. Graphic: ARN.

Cross-sectional diagram of major arterials in corridor, showing center LRT reservation, traffic lanes, sidwalks, and side-mounted TES poles for suspending the OCS. Graphic: ARN. (Click to enlarge.)


For such a configuration of an LRT reservation within a major arterial, constrained by narrow ROW width, San Francisco offers perhaps the closest operating example with the N-Judah Line of the Muni Metro LRT system that branches westward from the city center. For a roughly 10-block section along Judah St., from about 9th Avenue to 19th Avenue, LRT tracks are laid in a raised dedicated reservation that isolates them from motor vehicle traffic; eliminating the need for additional barriers such as channelization buttons or other separation devices, this design has the benefit of minimizing horizontal clearance.

As the photo at the top of this post illustrates, despite a ROW constraint of just 80 feet, this configuration of the major Judah St. arterial is able to provide the raised LRT reservation plus 4 motor vehicle lanes plus parallel sidewalks. It should not be difficult to envision a similar design working in Austin’s Guadalupe-Lamar corridor.

In the overhead view shown in the photo below, the top of a Muni Metro train can be seen in the center, running on the upper of the two tracks in the reservation. The different allocation of ROW space for traffic and sidewalk can be noticed — San Francisco provides an on-street parking lane and a traffic lane on each side of the arterial, plus sidewalks nearly 11 feet in width. In contrast, Austin Rail Now recommends that Guadalupe-Lamar would have 4 full traffic lanes of 10-ft width, no parking lanes, and 8-ft sidewalks.


Aerial view of Judah St. corridor segment, showing central reservation with Muni Metro LRT train, motor vehicle lanes on each side, and sidewalks on each side of arterial. Photo: Google Maps Satellite View.

Aerial view of Judah St. corridor segment near 10th Ave., showing central reservation with Muni Metro LRT train, motor vehicle lanes on each side, and sidewalks on each side of arterial. Photo: Google Maps Satellite View. (Click to enlarge.)


The following two photos at surface level showing Muni Metro trains in the Judah St. reservation further suggest how efficient LRT service can be installed in the relatively constrained arterial ROW of Austin’s Guadalupe-Lamar corridor.


In this view of single-car train on slightly raised median near 16th Avenue, transverse spanwire that holds OCS power wire can be seen behind train, suspended between TES poles on either side of street. TES poles also serve as street light masts, a typical dual function. PHOTO: Peter Ehrlich.

In this view of single-car train on slightly raised median near 16th Avenue, transverse spanwire that holds OCS power wire can be seen behind train, suspended between TES poles on either side of street. TES poles also serve as street light masts, a typical dual function. PHOTO: Peter Ehrlich.


In this view of a train near 15th Avenue, the slightly raised center median reservation can be seen more clearly. Over the train, transverse spanwires holding OCS can be seen; other cross-wires are general utility cables. Photo (copyright) Eric Haas.

In this view of a train near 16th Avenue, the slightly raised center median reservation can be seen more clearly. Over the train, transverse spanwires holding OCS can be seen; other cross-wires are general utility cables. Photo (copyright) Eric Haas.


There are other alternatives for installing LRT in the Guadalupe-Lamar corridor. To eliminate the need for TES poles, for example, there are “wireless” power options, but these tend to be proprietary, somewhat experimental technologies and substantially more expensive. Widening these arterials by acquiring more ROW is another option, but this also introduces greater expense. We believe that the raised-median design, with side-mounted TES poles, presented here, represents a particularly cost-effective, functional solution worth considering for G-L and other major Austin corridors. ■