Rates on the spot freight market posted gains last month compared to February and the same time a year earlier, according to the latest reading of the DAT North American Freight Index, based on activity from its load boards

This measure of conditions on the spot truckload freight market shows van rates increased 2.5%, flatbeds added 2.8%, and reefers were up 1.7%, compared to February.

Compared to March 2014, the gains were just as large if not bigger, with van rates up 2.5%, flatbeds increased 6.9% and reefer rates added 6.4%. Monthly average rates have increased year-over-year for more than 20 consecutive months.

This happened as spot market freight volume rose 34% in March compared to the previous month, a spring surge which is typical for the season, according to the DAT.

By comparison, March freight availability declined 28% year-over-year, pulling down the index from its level a year earlier. The spring freight season usually begins in late March, but a prolonged winter in 2014 led to unprecedented volume throughout the entire first quarter.

By equipment type, freight volume increased month-over-month: 34% for vans, 41% for flatbeds and 20% for refrigerated trailers.

Compared to the extraordinary market conditions of March 2014, year-over-year freight volume by equipment type declined 19% for vans, 42% for flatbeds and 1.3% for reefers.

According to DAT, intermediaries and carriers across North America listed more than 120 million loads and trucks last year on the DAT Network of load boards.