Although the Cambus system is mostly confined to campus, shuttling students from class to class, it is not immune to the effects of violence in the Middle East or weather in the Gulf of Mexico.

As gas prices continue to rise across the country, Cambus operating costs are also growing.

“We’ve been seeing a gradual increase in fuel prices over time,” said Brian McClatchey, the manager of Cambus. “It’s stabilized now, but it’s stable at a pretty high rate.”

Over the last 10 years, the amount Cambus spent on fuel rose from 81 cents per gallon to $3.42, not including tax. In other words, during fiscal 2002, it spent $147,000 on fuel, and in fiscal 2012, fuel costs rose to $781,000.

However, the cost of fuel is not the only number that has been climbing. McClatchey said the demand for public transportation has as well.

The Cambus system is not the only business affected by the rise in fuel prices. The Iowa City Public Transit has also noticed an increased burden in operational costs due to rising gas prices.

Chris O’Brien, director of Iowa City Transportation services, said fuel costs have increased about 33 percent over the last three years.

This rise in operational costs has led to historic changes.

“We raised our transit fares and passes for the first time in 15 years,” O’Brien said. “If the fuel costs continue to rise, it would lead to additional increases to fares and passes to cover those costs.”

The Coralville Transit noticed a strain on its budget as well. Although officials can’t pinpoint all of the direct effects of gas hikes, they do see a trend.

“Often as we see fuel spikes, we also see spikes in ridership,” said Vicky Robrock, the director of Parking and Transportation in Coralville.

Not all transportation departments are negatively affected, though.

Mike Wilson, the manager for the University of Iowa Fleet Services, sees a different result.

“It’s actually good for our business in some ways,” he said. “When gas prices go up, people will stop using their vehicles and use us more.”

One of the biggest fears for officials at the Cambus system is that the rises in fuel prices will be sharp.

“If it takes a sudden increase, that’s where you have to look at cutting back,” McClatchey said.

He said that if there is a gradual increase, the system can adjust to that. However, it can limit services and makes it difficult to expand.

Alternative fuel sources are also an option — but not always the best one. The Cambus system runs partly on biofuel, which adds about 15 cents to fuel costs.

“We’ve chosen to bear that expense to contribute to the university’s message of sustainability,” McClatchey said.

Electric hybrid buses are also an option, but are not cheap. McClatchey said they could buy three regular buses for the price of two hybrids.

“Being a small system, we are really limited in what we can do to move to alternatives,” he said.

“We applied for grants along with Coralville Transit and Cambus to procure hybrid buses in previous years but were not awarded funding,” O’Brien said.