I found that in presta mode, neither my bike pump, CO2 pump, nor my air gauge worked very reliably. A presta adapter only costs $3. Put it in with your patch kit (assuming the same patch kit for road and MTB) and you'll be ready to use whatever pump you want and/or emergency stops at gas stations (with your road bike).
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Cars kill 45,000 Americans every year.
This is like losing a war every year, except without the parades.