The price of oil is likely near a top and will likely fall beneath $100 a barrel by July 4, Gulf Oil CEO Joe Petrowski told CNBC Monday.

Consumers will put the brakes on car travel when gas reaches an average $4 a gallon, he said. At that price it costs drivers about $50 to fill a gas tank, he said, and that psychological level is the tipping point. The national average for the price of gas is currently $3.83.

"At these prices, and especially over time, people carpool, they bundle their trips," he said. "We’re starting to see it at all our 3,500 locations."

He sees the price of oil within a few dollars of a top. "I don’t think we’ll hit $125. I think by July 4 we’ll be under $100," he said.

He said world demand for oil is slowing. There are signs "this market is peaking out. I think we will see the peak, if we haven’t seen it already, in the next three to four weeks."