Up north thwere is phenomena called frost heave. Whenever there is trhe slightest porosity in a street & water gets in, then whenever that water freezes, it expands, and the porosity gets greater so the next time it freezes with water in the pores, it expands again & the hole gets even larger. Now remember that the sun warms the pavement some many days in witer, and it freezes most every night. So the phenomena of frost heave is working about once or twice each day for about 4-5 months a year. Where I lived in upstate NY, the last frost date for planting agarden was my birthday, May 27.