Background:
This study evaluates an innovative intervention aimed at increasing everyday physical activity in the workplace. The 13-story Caltrans District 7 Headquarters Building is the first major office building to use “skip-stop” elevators as the major way for workers to go to their offices. This means that many workers either walk up or down a floor to get to their office or walk a considerable distance to a secondary elevator bank. If successful, this intervention has considerable promise for both new construction and for renovation. In new construction is can reduce the cost of elevator equipment by 30% or more; in renovation is only requires eliminating access to some floors.

The skip-stop elevators in this building stop at every third floor and require building users to use an adjacent, easily accessible and potentially inviting stair to access the floor below or the two floors above. This design feature was conceived as a means to organize this high-rise building into a more human scale, increase personal interaction and overall office cohesion among Caltrans employees occupying the building and increase physical activity while decreasing non-productive time spent waiting for elevators.

Objectives:
This study evaluates the skip-stop intervention, exploring stair use by workers, their acceptance of this potentially-inconvenient arrangement and the rationale and strategy used to design it.

Methods:
The design of this block-long building provides a set of skip-stop elevators and stairs serving the north side of the building and a traditional elevator core (that stops at every floor) serving the south side of the building. This arrangement allowed for a natural experiment comparing stair use by employees at different end of the building; providing the opportunity to explore how a relatively simple building-scale intervention impacts physical activity.

The study used several methods:

• Monitoring. The study used active infrared monitors and card reader activity logs to measure and compare stair use on the skip stop stairs and enclosed stairwells over a 24-week period.
• Online Survey. An online self-report survey was used to collect data from Caltrans employees about the new building, the elevator/stair arrangements, their attitudes and behaviors towards physical activity in general and their workplace physical activity habits including stair use.
• Interviews. A wide range of participants were interviewed about their experience in the design process and in using the building: high-level Caltrans executives, managers, line workers, the architecture firm, and others.

Results:
Stair use data indicated that skip-stop stair use was 49.75 times greater than stair use within the enclosed stair of the traditional vertical circulation core, averaging 980 floor levels climbed daily within the four floors monitored in this study. Self-reported survey responses that indicated that 72% of the survey participants are using the stairs daily, equating to an average stair use of 1.9 floor levels/workday/person. When compared to the almost negligible use of enclosed stairs (0.06 floor levels/workday/person) found in the traditional elevator core arrangement, this data suggests that the skip-top stairs/elevator arrangement contributes to a substantive and widespread use of stairs in this building.

This level of stair use is notable especially as the survey indicated that Caltrans employee behavior towards physical activity is generally typical in regard to American adult patterns of physical activity. Only 12% of survey participants achieved the Surgeon General’s recommendation of 30 minutes of moderate physical activity most days of the week and 27.8% did not have any day where they achieved thirty minutes of moderate physical activity. Analysis of the relationship between floor level climbed and various self-reported health and workplace location factors did not indicate that the increased stair use was related to natural selection by healthier employees or those in close proximity to the skip stop stairs.
In addition, employees reported that they became increasingly positive about the skip-stop arrangement as they continued to use the building.

Conclusions:
The results of this study provides persuasive evidence that a push strategy such as the use of skip-stop elevators combined with associated open staircases will result in an increased and sustained level of stair use when compared to the traditional elevator/stair arrangements in office buildings.

Support:
This study was conducted by the Georgia Institute of Technology College of Architecture, PhD. program.  The study was supported by Robert Wood Johnson Foundation via Active Living Research.