Commonwealth Avenue stretches out into the background in the video and continues past the camera position on the right. University Road comes in from the left in the video. The right-turn lane for the Boston University Bridge passes to the left of the camera position.

Evidently, right turns on red are allowed from University Road. During the green phase for Commonwealth Avenue, motorists turn and merge four different ways across the sketched-in outline of a bike lane past University Road.

* Vehicles from University Road may turn right onto Commonwealth Avenue, to cross the Charles River on the BU Bridge --

* or they may merge into the middle lane of Commonwealth Avenue to go west.

* Most of the traffic in the curb lane of Commonwealth Avenue turns right across the bike lane, onto University Road, but --

* some traffic in the curb lane continues across University Avenue, then bears right across the bike lane onto the bridge. Some traffic in the middle lane of Commonwealth Avenue (including one vehicle shown) also bears right onto the bridge -- crossing the bike lane from the second lane to its left.

Two motorists in the video make clearly-illegal maneuvers. One, with right-turn signal blinking, enters from University Road, crosses to the left of the bike lane and then recrosses it to make the right turn onto the bridge. Perhaps the driver thought that the bike lane must be to the right side of all the other lanes, as is usual? Another driver makes a right turn from the middle lane of Commonwealth Avenue onto University Road, crossing a travel lane as well as the bike lane.

Bicyclists' best lane position on Commonwealth Avenue to continue straight ahead is in the middle lane, not in the bike lane to the right of all the right-turning traffic. The best position for a bicyclist to cross University Road and turn right onto the bridge is in the middle of the right lane. Timing of the traffic signal at the previous intersection could create gaps in the traffic, making it easy to merge to these positions.

The lane striping appears to have been designed under the assumption that motorists are capable of merging, but bicyclists are not. The path along which the bike lane directs bicyclists carries increased complication and risk of crashes for every destination except University Road. It requires bicyclists and motorists to merge across each other's path inside an intersection, as is prohibited under the traffic law of most states. (Massachusetts law is unclear about this).

This video is not entirely representative of final conditions, due to the incomplete line striping, the service vehicles that narrow the roadway, and perhaps changes in signal phases and timing. It will be interesting to return and observe conditions once the lane striping has been completed -- and when Boston University is in session and there are more bicyclists.