Effects of Seasonal Changes on Ride Quality at MnROADStatus: CompleteReport Date: 07/21/2008 Summary: Investigators found that frost heave, a common problem in winter weather, occurs less frequently and with less severity in thick pavements, in well-draining pavements and in those built over sand subgrades rather than clay subgrades. Final Deliverables: Report #2008-23 Research Summary Related Materials: Related Research: