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Table 19-27 is ordered by which strategies had the biggest changes in rank. At the top of the list, pas- senger loading areas gained 21 net points in rank, showers and lockers gained 15 points, marketing gained 8, direct financial incentives gained 7, and on-site services gained 6. Most of these measures are "soft" strategies, as previously noted in the "Voluntary Versus Regulatory Employer Motivation" discussion above. Ongoing transit subsidies fell by 17 ranking points, company vans by 7 points, and introductory tran- sit subsidies by 6 points. One should also look at the actual employee participation numbers as well as the rank change, in order to have a proper appreciation of the relative scale of each strategy's pop- ularity. For example, while SOV parking fees increased in rank by 2 points, this only represents a change in position from 34th to 32nd place. These SCAQMD-regulated employer shifts in strategy, with their failure to take on or even stick with much in the way of financial incentives and disincentives or transportation services, held trip reduc- tion to modest levels. Employment sites involved for the longest time period achieved, in 3-plus years, slightly over a 7 percent average reduction in journey-to-work vehicle trips per employee. Results from sites with greater progress were partially washed out in regulated-employer averages by diminished success on the part of a number of firms that actually started out with high perfor- mance. SCAQMD results are further discussed in the "Related Information and Impacts" section under "Site- Versus System-Level Impacts"--"Intermediate Effects of Dissipation." Land Use and Site Design A growing number of research studies have investigated the link between transportation and land use at the residential end of the trip, but fewer have probed the synergy between travel behavior and land use at the destination. It would seem reasonable to assume that a work site located in an attractive setting with good walkability, access to transit, and convenient proximity to attractions and services would find it easier to entice commuters from their cars. A major reason often given for driving to work is that the worksite is located in an area that is isolated from any other activi- ties, requiring a personal vehicle to tend to midday needs for lunch, errands, or going to meetings. A more complete discussion of such relationships is found in Chapter 15, "Land Use and Site Design." See also Chapter 17, "Transit Oriented Development," for additional information. Reported on here in Chapter 19 are two studies specifically designed to examine the relationship of employment area land use and site characteristics to TDM effectiveness. TCRP Project B-4, introduced earlier and described in Footnote 2, obtained information via survey from 50 different employers on their TDM programs and also on employer and site characteristics. With this information, an attempt was made to determine the approximate number of services reachable within a 5-minute walk. Correspondence between this local accessibility and the calcu- lated VTR was found to be surprisingly strong. The 11 employment sites rated as having "poor" access to services (2 or less) averaged a VTR of only 5.3 percent. The 11 sites rated as having "fair" access (3 to 5 services) averaged an 8.3 percent VTR, while those 25 with "good" access (more than 5 services) averaged 21.5 percent. Influences beyond local accessibility were quite possibly a factor--the accessibility measure may have acted as a surrogate for urban conditions in general. The types of TDM programs implemented in these various settings do show some important differences, with 23 of the 25 programs in the "good" access category offering financial incentives. On the other hand, eight of the 11 programs in the "fair" category and seven of the 11 in the "poor" category also offered financial incentives (Comsis, 1994). 19-98
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A more deliberate and comprehensive attempt to investigate the synergy between land use and TDM impact was made in a study for the Federal Highway Administration (FHWA). The researchers selected a sample of 330 employment sites in Los Angeles County that were participating in the Regulation XV program, and appended information on a wide range of land use and site design characteristics to existing data file information on TDM program characteristics and employee travel. The expanded data were then analyzed both descriptively and statistically. Overall, the sample of 330 programs indicated the following shifts in behavior in relation to the first Regulation XV plan (Cambridge Systematics, 1994): · Drive-alone share decreased from 76.2 percent to 71.4 percent, while carpool/vanpool share increased from 13.4 percent to 18.8 percent. · Small mode share losses were incurred by both transit (down from 4.6 to 4.4 percent) and bike/walk (down from 5.8 to 5.4 percent) as an apparent result of the initial program. It is not clear whether this outcome reflected an overemphasis on programs and incentives for ridesharing (as suggested by the study) or whether transit and bike/walk were simply not as viable as ridesharing in this travel market. Flexible work schedule shares (telecommuting and CWW) also declined, from 3.8 to 3.1 percent. AVR increased from 1.213 to 1.245, equating to a VTR of 2.5 percent. The 330 sites were a randomly selected subsample from a database of 1,100 employers who had completed at least one trip reduction plan under Regulation XV. The land use data were compiled for the following three different levels of geographic resolution (Cambridge Systematics, 1994): · The surrounding subarea (1/2 to 2 square miles), recording land use mix, predominant land use type, building types and special features, main streets, traffic levels, sidewalks, and landscaping. · The immediate environs (1/4-mile radius), recording horizontal and vertical land use mix, spe- cific land uses present, number and type of and distance to services, street characteristics, "streetwall" characteristics, sidewalks, pedestrian activity, and landscaping. · The actual site, recording the number and characteristics of parcels and blocks, building archi- tecture, size and orientation, on- and off-street parking, access to bus stops, sidewalks, and street life. The research approach was to then try to explain the change in modal share for the 330 employers based on both the characteristics of their TDM programs and the land use characteristics of the sites. Given the large number of TDM strategies and land use/site descriptors, it was found nec- essary to pare and consolidate the list of measures into index-type variables. TDM program strate- gies were divided into five categories: assistance programs, financial incentives, awards programs, flexible work schedules, and other. The land use characteristics were also partitioned into five cat- egories, as follows: · Mix and variety of land uses within 1/4 mile. · Availability of convenience services (number and mix of key services within 1/4 mile). · Walk accessibility to convenience services (design of area to promote walking). 19-99
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· Perception of safety (sidewalks, street lights, pedestrian flow, number of vacant lots). · Aesthetics (sidewalk widths, landscaping, absence of graffiti). Initial analysis of the link between the observed changes in mode share and the TDM strategies applied at the 330 employers revealed that only financial incentive strategies were statistically sig- nificant. Therefore, for the TDM aspect of the analysis the researchers basically distinguished pro- grams (employers) with financial incentives from those without. The five land use measures were similarly treated as having a "low" or "high" value for the particular index. A summary of the find- ings corresponding to this structure is presented in Table 19-28 (Cambridge Systematics, 1994). Overall, the findings suggest that for drive alone, carpool/vanpool, and flexible work schedules, the impact of the TDM financial incentives is measurably more important on changing share than any of the land use measures. In fact, for carpool/vanpool, better land use--specifically as represented by land use variety, availability of convenience services, and walk access to services--actually was associated (at least in the model) with a decrease in the use of that mode. With transit, however, and to a lesser extent bike/walk, supportive land use proved to be very important, increasing the shares for these modes. It is also interesting to note that the combination of financial incentive TDM programs with better land use is almost always synergistic, i.e., it produces a higher net effect on both mode share and AVR than the two measures independently. The notable exception is carpool/vanpool, where combining the measures was identified as being detrimental to carpool/vanpool share in all but the category of aesthetic appeal, which--somewhat surprisingly--is overall the most influential measure of land use identified by the study. It is difficult to comprehend how the elements cap- tured in the aesthetics measure would have more influence on mode share than the other four mea- sures, unless the measure is somehow acting as a surrogate for other aspects of the environment that were not captured by the set of indices. 19-100
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Table 19-28 Combined Effect of TDM Financial Incentives and Land Use Characteristics on Mode Share and AVR Modal Share with Low and High Prevalence of Specified Land Use Characteristics Availability of Walk Access to Presence of TDM Variety of Convenience Convenience Perception of Financial Incentives Land Uses Services Services Safety Level Aesthetic Appeal (Without/With) Low High Low High Low High Low High Low High Drive Alone Without 77.2% 75.2% 76.7% 75.2% 76.4% 76.0% 79.0% 75.1% 77.0% 72.4% With 71.7% 70.8% 72.4% 69.6% 72.1% 70.5% 73.2% 70.6% 73.2% 66.6% Transit Without 3.6% 5.5% 3.7% 6.1% 3.5% 5.5% 3.9% 4.8% 3.9% 7.8% With 2.9% 6.4% 3.4% 7.1% 3.0% 6.3% 3.6% 5.4% 4.2% 8.3% 19-101 Carpool/Vanpool Without 13.4% 13.0% 13.4% 12.5% 13.8% 13.0% 12.8% 13.6% 13.3% 13.9% With 18.7% 17.7% 18.6% 17.5% 18.8% 17.7% 18.4% 18.0% 17.9% 18.9% Bike/Walk Without 3.0% 3.6% 2.9% 4.0% 2.9% 3.6% 2.2% 3.7% 3.2% 3.9% With 2.6% 3.1% 2.6% 3.3% 2.2% 3.3% 1.7% 3.2% 2.6% 3.9% Flexible Work Schedules (Percent Flexing Schedules Without and With Financial Incentives) Without 2.4% 2.7% 2.4% 2.8% 3.4% 1.8% 2.2% 2.7% 2.7% 2.0% With 4.0% 1.9% 3.0% 2.4% 3.8% 2.1% 2.9% 2.7% 2.9% 2.3% AVR Without 1.218 1.229 1.224 1.223 1.225 1.222 1.206 1.230 1.211 1.285 With 1.230 1.271 1.230 1.286 1.229 1.272 1.229 1.263 1.235 1.337 Source: Cambridge Systematics, Inc. (1994).