The entire stretch of Arapahoe (Highway 7) between Boulder and Lafayette should have been widened out to 4 lanes years ago.  But Boulder (city and county) keeps trying to discourage driving; so when Arapahoe was "improved" recently between 63rd and 75th Streets they only added bike and bus lanes.  They never added the sorely needed general purpose traffic lanes.  THAT is why Arapahoe continues to get backed up for miles every day with the morning and evening commute.


Until Boulder traffic planners pull their heads out of the sand and actually widen Arapahoe to 4 GP lanes, that road will continue to stay clogged.  They can dream on all they want about forcing (aka "encouraging") folks into taking buses and bikes to work; but that kind of social engineering doesn't cut it.  The people who live along that stretch of road, and who vote those clowns into office, need to demand that widening.  Until then, Arapahoe will just continue to get worse with more idling traffic and exhaust fumes.