While spot truckload freight rates showed some improvements in May from the month before, they remain well below levels from a year earlier, according to new figures released by the freight matching service provider DAT Solutions.

The DAT North American Freight Index, based on the company’s load board activity, shows average line haul rates on the spot market increased 1.5% for vans and 4.3% for reefers. During the latter half of May, however, rising rates on the top 80 van lanes far outnumbered declines, indicating rates were following increased demand. Flatbed rates declined 0.6%.

Spot freight availability in May increased 19% for both dry vans and refrigerated vans. Flatbed freight, however, declined by 10% month-over-month largely due to energy sector woes impacting Houston, the top flatbed market in North America, according to DAT. Consequently, overall spot market freight volume increased 5%, compared to April.

This news comes as weekly figures released by DAT the day before shows spot rates are showing some season improvements as June began and are expected to continue increasing, at least for the near-term.

Meantime, when May is compared to a year earlier overall spot market freight availability fell 25%.

“Spot freight has declined year-over-year since January 2015,” said DAT. “Contributing factors include vastly increased contract carrier capacity and intermediaries tendering exception freight to their core carriers.”

Demand declined 25% for vans, 28% for reefer trailers and 26% for flatbed freight. Likewise, year-over-year line haul rates fell 14% for vans, 11% for reefers and 8% for flatbeds.

“Total carrier revenue has been impacted by a 35% drop (10 cents per mile) in the fuel surcharge compared to last May,” said DAT. “The total rate includes both the line haul rate and the surcharge, which is pegged to the retail cost of diesel fuel.