Apr 09, 2012

Although specialized equipment and vehicles make up a large portion of state transportation budgets, an OTREC research report found little consistency in how states decide to replace this equipment.

Researchers David Kim and David Porter of Oregon State University surveyed 25 state departments of transportation to determine how they made replacement decisions. Nearly all consider the age of the vehicle or piece of equipment, with many considering how much use it gets.

Around half use thresholds, such as number of miles or months in service, to identify candidates for replacement. Some consider the equipment’s repair cost or operating cost, while others rely on physical inspections. None explicitly considers greenhouse gas emissions or other environmental concerns in its replacement criteria.

Given the huge range of approaches, Kim and Porter wondered if modeling could lead to better decision-making. They ran various models against the simple approach of using equipment age as a threshold value.

As it turns out, the simple approach isn’t too bad. In fact, it does better than one complicated mathematical model and about the same as a second model.

Click here to learn more about the project and download the report.

That may...

Read more
Mar 09, 2011

Fleet managers can benefit from buying electric vehicles under certain conditions, according to a research paper by Portland State University associate professor Miguel Figliozzi. The paper marks OTREC’s first electric vehicle-related research accepted for publication in a peer-reviewed journal.

In the paper, set for publication in the Transportation Research Record, Figliozzi presents a vehicle replacement model that compares the benefits of conventional and electric vehicles under various scenarios. Incorporating electric vehicles makes the most sense for heavily used fleets when gasoline prices are high, assuming electric vehicle tax credits continue.

Until their purchase price drops, electric vehicles won’t make financial sense for fleet managers without some incentives. “Tax credits are important, especially at the beginning, given the higher price of EVs,” Figliozzi said. “The federal tax credit is roughly 20 percent of the (Nissan) Leaf’s list price and it makes a difference.”

The model presented in the paper shows that fleets will start to include a few electric vehicles with gas at $4.10 per gallon, assuming the existing tax credits. In heavily used fleets, defined...

Read more