Ground, water and winter in Hillsdale
Mid-county upland soils formed in loess, and the St. Louis County soil survey lists low strength and frost action as the limits for local streets, with adequate base material plus ditches and culverts as the fix. Water under asphalt through a freeze-thaw winter is what breaks it apart.
Before you sign anything, get the base depth and the compacted asphalt thickness on paper. Two bids that look far apart are often just two different pavements.
Compacted asphaltTypically 2 to 3 in. for a car drive
Stone baseTypically 4 to 8 in., compacted
Drive on itUsually 2 to 3 days, longer in heat
First sealcoatTypically 6 to 12 months after paving
Typical ranges. Your Hillsdale estimate is sized to the soil, the traffic and the drainage on your property.