University of California Transportation Center

The impacts of the Loma Prieta earthquake on Bay Area trucking firms, based on a combination of in-depth interviews and a random survey, are reported. The earthquake's primary impact on truckers derived from the closure of major roadway facilities, which necessitated circuitous routings and increased congestion on the facilities that remained open. The vast majority of truckers rated the impacts from increased congestion and circuitous routings as moderate or severe. Other impacts affecting substantial proportions of truckers involved communication and dispatching efficiency. The most common responses to the earthquake involved rescheduling, rerouting, and acquisition of additional labor. Service adjustments were also fairly common. Overall, truckers' costs increased an average of 7 per cent and while their revenues declined 5 per cent in the four-week period after the earthquake. The variation around these averages was considerable.

Correlations between firm size, use of affected roadway facilities, impact severity, responses, and cost and revenue changes were investigated. Truckers reporting greater use of affected facilities also reported greater impacts. Impact severity, was in turn, correlated with the number of countermeasures taken, as well as cost and revenue changes. Percentage reductions in revenue were also greater for smaller firms. No relationship between the number of countermeasures and cost or revenue changes were observed.

The overall impression is that the impact of the earthquake on Bay Area truckers was substantial, but not debilitating, largely because of the ubiquity of the roadway system and the fact that most firs escaped serious damage to their facilities and equipment. Future efforts to maintain and enhance this resiliency should focus on assuring minimal property damage, enhancing mechanisms for acquiring additional labor on a short-term basis, and improving communications.