In our Tuesday post on the Tri-State Transportation Campaign’s latest “Most Dangerous Roads for Walking” report, we noted the concentration of pedestrian deaths on Broadway in Washington Heights, where pedestrian islands, protected bike lanes and other safety features are not present above 168th Street.

In addition to engineering, another factor in pedestrian fatalities and injuries is, of course, traffic law enforcement. In the 33rd and 34th Precincts, which cover Washington Heights and Inwood, very few motorists are penalized for reckless driving — even those who cause grievous injury.

Washington Heights is an entrance and exit point for the George Washington Bridge. And with two toll-free bridges connecting Manhattan to the Bronx, and, ergo, Westchester County, Inwood is plagued by cut-through traffic (a problem that could be exacerbated by toll hikes on the Henry Hudson Bridge). We wrote that speed enforcement in the 34th Precinct effectively stopped after the installation of Manhattan’s first “Slow Zone” last October, but there wasn’t much enforcement to speak of before then either.

In 2011, the most recent year covered by the Tri-State report, and the first year in which NYPD made traffic summons and crash data available to the public, the 34th Precinct issued just 17 speeding summonses, and 152 summonses for failure to yield to a pedestrian. To the south, the 33rd Precinct issued 108 summonses for speeding, and 80 summonses for failure to yield, for the entire year.

Four pedestrians were killed by motorists in the 33rd Precinct between 2009 and 2011, according to Tri-State. In the 34th Precinct, eight pedestrians died in traffic during that period. Injury numbers by precinct are not known, since NYPD did not begin releasing that data until the middle of 2011.

It isn’t as if these precincts aren’t enforcing any traffic laws. In 2011, the 33rd Precinct issued 1,652 summonses to motorists for using a cell phone, the most tickets issued that year for any violation. Officers also wrote 1,160 summonses for seat belt violations, and 301 for tinted windows.

The 34th Precinct issued more summonses for seat belts than any other infraction in 2011, with 1,235 tickets. They wrote 1,220 summonses for cell phone use, and 1,025 for tinted windows.

Both precincts saw a dramatic rise, percentage-wise, in speeding summonses the following year: from 17 in 2011 to 52 in 2012 in the 34th, and 108 to 154 in the 33rd.

For some perspective on the scope of the speeding problem in Upper Manhattan, there were 37,292 daily vehicle trips over the Broadway Bridge, which connects Inwood and Kingsbridge, in 2010. If 39 percent of those drivers were speeding — the figure calculated by Transportation Alternatives in a 2009 city-wide study — that’s around 5.3 million instances of motorists putting lives at risk with the tacit approval of Ray Kelly’s NYPD.