Page 193 - TransportationPlanUsetsGuide

Transit-supportive densities are based on the number of households and jobs per acre in traffic analysis zones (TAZs)
as forecast for 2035 in the Regional Travel Demand Model. The generally accepted minimum density needed to support
regular transit service is three households per acre or four jobs per acre. This analysis goes further, matching increasing
densities with more frequent transit service. First, households and jobs are combined into a single unit of measurement
– “household/job equivalent units” (HHJEUs) – by multiplying the number of jobs in a TAZ by 0.75 and then adding
them to the number of households in that TAZ. Dividing the resulting number by the gross acreage of the TAZ results in
density; which is then assigned to one of the following classes:
• 0 – 2.99 HHJEU/acre: not a transit-supportive density,

• 3 – 5.99 HHJEU/acre: appropriate for LOS E (45-60-minute or less frequent headways),
• 6 – 8.99 HHJEU/acre: appropriate for LOS D (30-minute headways),
• 9 – 11.99 HHJEU/acre: appropriate for LOS C (20-minute headways),
• 12 – 19.99 HHJEU/acre: appropriate for LOS B (15-minute headways), or

• 20 HHJEU/acre or greater: appropriate for LOS A (7.5-minute or more frequent headways).

Transit service areas, classified by frequency level of service, are overlaid with TAZs, classified by households and jobs
per acre. The two measures are compared by performing a spatial join. Any given location can then be described as not
served, underserved, appropriately served, or well served by transit. These conditions are illustrated in Figure 3-29. Ac-
cording to the analysis, areas that would be underserved by existing transit service in 2035 include:
• Northwestern Forest Grove (prior to the implementation of GroveLink service)
• Most of job-rich north Hillsboro, from Brookwood Parkway eastward to the Tanasbourne/Amberglen area,
• The entire urban portion of the Cornelius Pass Road corridor, from West Union to South Hillsboro,

• Areas of Bethany that are not near the town center or Bethany Boulevard, including North Bethany, Laidlaw
Road (east of Bethany), and 174th Avenue,

• Cedar Mill Town Center,
• The 158th Avenue corridor from Sunset Highway to Jenkins Road,

• Raleigh West industrial area in Beaverton, centered on the intersection Western Avenue and Allen Boulevard,
• Washington Square Regional Center on both sides of Highway 217,
• Progress Ridge, Bull Mountain and urban reserves to the north and west,
• The Tigard Triangle and 72nd Avenue employment areas near the I-5/217 interchange,

• Southern areas of Tigard, especially along Durham Road,
• The Tualatin-Sherwood industrial employment area, and
• Southern and western neighborhoods of Sherwood.

Many of these areas are underserved based on present densities and transit service. Areas shown as well- served
include less-densely developed places than what a high-frequency transit route would typically serve. Such areas often
correspond with single-family neighborhoods and suburban retail areas near frequent service transit lines including
MAX, bus #57–TV Highway and bus #52–Farmington/185th. Portions of Aloha, Cornelius, Rock Creek, and Raleigh
Hills meet this description and benefit from it. Being well served by transit does not mean that transit service should be
reduced or that transit headways should be longer in these locations. It may indicate where denser development could
be feasible, if a number of other criteria were met, including support by the community and local officials. Many other
factors play a role in transit demand and ridership, including the demographic and socio-economic characteristics of
neighborhoods (especially income and age), the safety and “walkability” of areas near transit stops, the reliability of
transit service, and qualitative perceptions about the transit experience.

PART 3: TRANSPORTATION MODAL ELEMENTS 173
Effective November 27, 2015 • Updated December, 15 2016