And those tankers are waiting for a few more $/barrel to make this expensive form of storage really pay for itself. It's looking like they'll probably get it.

why is oil going up?

Jobs are not as bad as thought... But remember even in this nasty recession we've been trading at ~$50/barrel, which is a much higher floor on the price of oil than we had a few years ago...

Oil jumps ahead of supply report
Futures advance as stocks cheer signs of life in the job market. Government report is expected to show the nation's supplies of crude grew by 2.2 million barrels last week.

Oil prices rose nearly 3% Wednesday after two reports on the job market raised hopes the economy may be stabilizing.

The advance comes ahead of a government report that is expected to show the nation's already flush crude supplies grew last week.

Light, sweet crude was up $1.58, or 2.9%, at $54.43.

Automatic Data Processing, a payroll processing firm, said private-sector employment decreased by 491,000 in April, a 31% improvement from the revised 708,000 drop in March. Economists had expected a loss of 643,000 jobs.

Separately, outplacement firm Challenger, Gray & Christmas Inc. reported that the number of announced layoffs fell for the third consecutive month in April, dropping 12% to 132,590.

I have my own theories about the decline in vehicle miles.
There were a lot of people who could barely, marginally afford to own and maintain a car and with the economic downturn; have given up their car entirely. I'm talking about people who are barely employable; maybe with drinking or drug problems perhaps with $1000s in tickets from drunk driving or reckless driving; illegal immigrants; people living in the inner city with $1000s of unpaid parking tickets; seniors who maybe are not able to react fast enough.
Many of these people are barely able to manage owning a car in the best of times, and the economic slowdown has pushed them over the edge.
Don't forget that the majority of people are very horrible with managing money. Add in an expensive potentially dangerous car, some alchohol, bills; and the result is not pretty.
The second factor is the housing bust. Millions of real estate agents are not out showing homes. Less construction workers driving around in F350s. Less mortgage brokers buying new H3s with their bonuses and HELOC money.