tonto.eia.doe.gov/oog/info/twip/twip_gasoline.html#stocks

Gasoline stocks (storage, reserves etc.) are down, IOW there's less of it.  When there's less Elmo dolls than the demand of the market the Elmos end up costing more.  The normal cycle of prices includes the two changeovers from heating oil to gasoline and then back, before winter and before summer.  The time this happens is adjusted according to the weather and the market.

The trend is for higher prices but 3 years of prices show that's what it is...A TREND....not speculation.

www.gasbuddy.com/gb_retail_price_chart.aspx?time=24  Click on a 3 year chart to see the rise in prices in March and April EVERY YEAR.  

ETA also remember there is the factor of inflation, 3% might add 6 cents PER YEAR, or 18 cents (plus tax) to a gallon.