Kurani, Kenneth S., Thomas S. Turrentine, Sean A. Co (2000) Employee Travel in Yosemite National Park. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-00-03
The primary data source is a survey of employees. The timeframe was the summer of 1999. Employees of Yosemite Concession Services Corporation were surveyed in August; employees of the Park Service and of the "park partners" were surveyed in September. The park partners include the Yosemite Association, Yosemite Institute, U.S. Post Office, U.S. District Court, The Ansel Adams Gallery, and the medical/dental clinic.
As the employment and residence location of employees has a strong effect on work-related travel, this report is organized around locations. After a general description of the sample and population estimates, we look at employee travel in Yosemite Valley, El Portal, Wawona, Tuolumne Meadows. For each, we describe differences in work travel between those people who both live and work at each location, and those who commute from some distance away. As one would expect, those who live near their workplace have brief commute trips, which many accomplish by walking or cycling. Those who commute from some distance typically spend 45 minutes commuting each way; most do so by driving alone or in carpools.
Carpooling was the preferred commute travel mode of most people who currently drive alone to work. Just over half of Yosemite employees commute to work by driving alone at least sometimes; about one-third commute exclusively by driving alone. We had expected that among those employees who drive alone to work, their preferred options to driving alone would be shaped by where they worked. However, it appears that current experience with alternatives to driving alone is more important. For example, someone who already carpools occasionally is most likely to list carpooling as their preferred alternative.
Among those who ever drive alone, only one-fourth adamantly refuse to consider alternatives. The most frequently cited single reason that people were unwilling to consider alternatives to driving alone is the need to fulfill personal, familial, and social obligations either on the way to work, or more typically, after work. This reason is both the first most likely response and the most likely response when added across all three possible responses. Other common responses related to this idea are "Independence, convenience of own car" and "Unable or unwilling to rely on coordinating with others." In aggregate though, work schedules are an even more frequently cited reason for not considering an alternative to driving alone. A combined 44% stated that either their work shift was too early or too late, or that their work hours were too variable to allow them to use an alternate to driving alone.
We conduct two analyses of commute travel along the State Route 140/El Portal Road. This route connects the town of Mariposa, the Midpines area, the Park Service Administrative Area in El Portal, and Yosemite Valley. First, we estimate the potential size of the user group for a commuter bus service. The estimate—which amounts to some 360 employees per weekday—is derived from a set of assumptions regarding workplace and residence location, as well as daily and seasonal work time patterns. These people represent 17% of the current employees at El Portal or in Yosemite Valley. The single assumption which excludes the most people is the assumption that people who both live and work at the same place are not part of a commuter bus market. 35% of the employees at El Portal also reside there; 62% of employees in Yosemite Valley currently reside there.
Second, we estimate the portion of traffic on State Route 140/El Portal Road that is due to Yosemite employee commute travel. Depending on the direction of travel, the location along the road, and assumptions about the precise commute trip mode shares on any given day, the estimates are on the order of 10 to 20% of daily traffic.
Commute travel is highly concentrated in time. The percentage of eastbound traffic at El Portal during the peak morning commute hour of 7:00 to 8:00 that is due to Yosemite employees is estimated to about 75%. During the peak afternoon commute hour of 17:00 to 18:00, the percentage of westbound traffic at El Portal that is due to Yosemite employees is estimated to be between 34 and 41%.
The afternoon employee peak commute time corresponds to the beginning of the visitor peak traffic flow leaving Yosemite Valley. This correspondence in time of employee and visitor traffic on this road, coupled with the physical impediment to traffic flow represented by the roadway configuration at the Arch Rock Entrance Station, leads to congested traffic at this location in the early evening.
Park planning alternatives which remove employee housing from Yosemite Valley may increase employee travel on roads leading to, and entering, the park, but will also increase potential transit populations. The largest share of current employee commute traffic moves along SR140/El Portal Road. Increases in employee traffic along this route may not impact visitor experience if that increase occurs at the same time as, or earlier than, the current morning Yosemite employee commute. Increasing employee traffic during the exiting afternoon/evening commute period appears likely to exacerbate an existing traffic congestion problem. Policies and programs to promote transit use—among employees and visitors—can facilitate the elimination of afternoon traffic queues at Arch Rock.