Alan from Aurora writes, “The intersection of Arapahoe Road heading east and Buckley Road going north -- there have been many serious accidents at this intersection and I think I know the reason. The problem is, there is a left green arrow signal for traffic going east on Arapahoe road and turning left onto Buckley. This traffic signal intermittently turns into a green light. Motorists then will sometimes mistake this green light for a green arrow and dangerously make the left turn into the intersection directly into the pathway of speeding traffic coming west on Arapahoe Road. This is where frequent, serious accidents occur. This could easily be made much safer, if the green light of the left turn signal was changed to a flashing YELLOW light! This would eliminate the confusion of drivers wishing to turn left at Buckley Road. This needs to be done quickly, before the next accident happens.”
Alan, that is one of the busiest and heavily traveled intersections in unincorporated Arapahoe County with well over 50,000 vehicle per day using it. Traffic engineers tell me the intersection is dangerous because the dual turn lane from Arapahoe to Buckley crosses three lanes of westbound traffic where oncoming vehicles on Arapahoe Road routinely drive 50 to 55 mph.
You are also correct about the high number of collisions at this very, busy intersection. Arapahoe County Public Works has conducted numerous studies over the past several years looking at how drivers use that turn. These ongoing “evaluation periods” were started, Public Works tells me, due to the significant amount of accidents that is occurring at this intersection -- all related to the eastbound left turn.
In 2013, there were ten accidents involving that eastbound left turn between 8 a.m. and 11:30 p.m. Half of the accidents occurred at night between 9 p.m. and 11:30 p.m. Six of the ten occurred late in the year in July, August and September.
The goal from an operational and safety standpoint for any traffic engineer is to keep accidents and delays to a minimum at any intersection. Arapahoe County Traffic Operations Manager, Jerry Maschka, said after that extensive study in 2013 some changes were implemented.
“That evaluation lead the County to operate the eastbound left turn phase as a protected-only movement during specific hours of the day and night and as a protected/permissive-movement at all other times of the day. This adjustment worked for a period of time as accident frequency was reduced,” said Maschka.
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That success was short lived. During the accident evaluation period during the first half of 2014, they again saw a spike in the frequency of collisions outside the times of protected control. Maschka told me they had to make another adjustment to the operational times of the eastbound left turn to a “more restrictive time frame”.
Maschka said even though the number of crashes was down, in July of 2015, the County determined that another change to the operation of the eastbound left turn signal was needed due to the number of crashes still occurring during left turns.
“Since July of 2015 to present day, the eastbound left turn phase is running a protected-only operation on weekdays from 7 a.m. to midnight and a protected/permissive-operation from midnight to 7 a.m. On weekends it runs protected/permissive from 5 a.m. until 7 a.m. Monday morning. Under this control, we are not aware of any heightened accident activity occurring from the point of this operational change to present day,” Maschka says.
As for your idea Alan [that a flashing yellow light would solve the problem], Maschka told me they don’t believe that would be the case.
“Based on past accident history related to the allowance of permissive control at this location, being a permissive-type operation, we do not believe that a flashing yellow arrow control would increase the safety at this location vs the periods of current protected-only operations being run,” Maschka says.
Arapahoe County isn’t against the flashing yellow arrow at the intersection idea. They have one signal using it and has plans to install several others at existing traffic signals before the end of the year. They have a long term goal to install them at all County traffic signal locations at some point in time.
The county doesn’t have accident data from the past few months, but Maschka told me they have not received any reports of excessive accident activity there by the Colorado State Patrol.
I think you can be assured that the traffic engineers in Arapahoe County are looking into every possible technology to reduce the number of crashes at this intersection to zero.
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