Cover Image

Not for Sale

View/Hide Left Panel
Click for next page ( 45

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 44
44 designed, and constructed. Under this framework, an effort with comparative travel times for freeway and transit to reach is made to account for how a corridor is given or has taken their corridor destinations, encouraging peak-period mode on multimodal features. Here, we propose a continuum that shifting. Sidewalks, paths, and bicycle routes might be added distinguishes between the degree to which a multimodal cor- to the existing surface street network to encourage more non- ridor has developed as a result of an explicit intention or is automobile circulation along the corridor and non-automobile the incidental result of a series of planning and investment connections between modes. decisions over time. Another important option along this continuum is the To the degree that the multimodal features of facilities-- transit retrofit approach. Located near the incrementally transit and freeways--are designed by intention and at the planned side of the scale, a transit retrofit project involves the same time, we refer to them as concurrently planned. To the addition of a transit line to a pre-existing freeway facility degree that the multimodal features of corridors arise over (such as in the case of Denver's T-REX/I-25 corridor) and time, organically or as a result of incremental measures, they its surrounding corridor. This approach is distinguished by are referred to as incrementally planned (see Figure 4-7). the high costs involved in redesigning and reconstructing At one end of this continuum is the concurrently planned the freeway facility (or its immediate environment) relative multimodal corridor. A hypothetical, pure example of such a to the purely opportunistic/incremental approach described corridor is one where all transportation facilities were planned, above, but its costs are relatively low compared to the inten- designed, and built at the same time and in a coordinated tionally planned system described above. Typically, the designs fashion. In this way, the full performance potential of the of capital-intensive transit systems (historically rail but increas- multimodal system can be realized, with each mode both ingly bus rapid transit) are driven more by short-term cost- supplementing and complementing the others in a coordinated minimization through retrofitting than long-term ridership whole. The surrounding land use context within the corridor development-maximization principles. could also develop in response to this coordinated multimodal Also falling in the midrange of the continuum are multi- system, ideally providing an optimized transportation and modal facilities where the plans for and the reality of their land use interface. operations and constructions diverge over time. Planned facil- At the other end of the continuum is the incrementally ities can become obsolete, or conflicting plans developed by planned multimodal corridor. Here, each corridor component different stakeholders (for example, transit agencies, freeway has been designed and built in an incremental fashion. In this departments, or local land use authorities) can result in sub- extreme case, there will be few if any functional connections optimal operations and outcomes. between the various modes running in the corridor--transit, Table 4-9 suggests how this tradeoff can serve the purposes freeway, pedestrian, and bicycle facilities will all operate of developing a new paradigm corridor to have market seg- relatively independently with few transfers between systems mentation and an optimized corridor orientation. and in an uncoordinated fashion. Gradually, incremental (and often inexpensive) connections will be made between Summary and Conclusions the modes to create a more cohesive and coordinated multi- modal corridor system. Shuttles may be set up to run between The key to planning, designing, building, and operating a freeway park-and-ride lots and transit stations to encourage successful new paradigm multimodal corridor is to provide intermodal transfers. Traffic information management sys- segmented, distinct travel markets within the corridor that each tems may be installed along the freeway to provide motorists mode can serve. Segmented multimodal corridor markets can Concurrently Planned Incrementally Planned Planned & Constructed at Same Time Planned and Built at Different Times Highly Coordinated or Combined Agencies Incremental Approach to Coordination High Potential Aggregate Cost Savings High Potential for Cost Savings High Potential for Complementary Performance Figure 4-7. The multimodal planning continuum.

OCR for page 44
45 Table 4-9. Intentional versus incremental transit routing tradeoff outcomes. Concurrently Planned Incrementally Planned Market Segmentation High level of segmentation Intermodal transfers/Transit possible as congestion relief to freeway Corridor Orientation Transit-oriented Automobile-oriented generally be classified as having either a transit or auto- Transit-oriented versus automobile-oriented urban form mobile orientation. This chapter identifies the following Local access versus intermodal transfer stations tradeoffs that can be made when planning a new paradigm In-median and adjacent versus offset freeway alignment corridor: Supplementary versus complementary transit and freeway service Transit corridor accessibility versus operating speed Fixed versus flexible transit routing Freeway accessibility versus operating speed Incremental versus concurrent corridor planning Freeway capacity versus transit ridership approaches