It hasn't been pretty lately for those driving vehicles lately, and it will likely get worse this week in much of the U.S. and Canada.

Wholesale gasoline prices continue to march higher, and oil prices continue to add upward pressure to the mix. Fires at refineries across the U.S. certainly aren't helping the mix.

In the last week alone the national average has risen 5c/gal, and while that doesn't sound significant, prices are now up a whopping 25c/gal over the last month. Two of the lower 48 states now boast $4/gal average price for gasoline- Illinois and California, while the lowest state, Arizona, stands at $3.33/gal, up 7c/gal in the last week.

Word is hitting presses this morning that Chevron, while not making a public statement, will likely see its Richmond, CA refinery down for months. Significant downtime, while good for other refineries in the region, is bad news for motorists. The West Coast is already looking at tighter inventories than last year, and also declining inventories as a fire earlier this year diverted badly needed inventories to the upper West Coast.

Great Lakes motorists also saw another bump up last week in their retail price, even after wholesale gasoline prices took a bit of a respite. About the only region that is seemingly dodging the big increases is the Rocky Mountain region, with Wyoming only seeing average prices rise 4c/gal in the last week.

It is certainly possible that this is all temporary, and it is indeed likely that prices peak in the weeks ahead before falling again in late-September and October. Historically, gasoline prices bottom out between Thanksgiving and Christmas, so motorists can see a little light at the end of the tunnel- but for this week- the pain at the pump will worsen.