This was found through googling "how many police officers are shot yearly", seems reliable (129 in 2017);
http://nleomf.org/facts-figures/officer-deaths-by-year
There is more on that google search page. Take note that the above number seems to be deaths and not so much shootings so I'd assume this included traffic related deaths.
This is what wikipedia says for 2018;
2018[edit]
The Officer Down Memorial Page reports 149 deaths in the line of duty.[22] The National Law Enforcement Officers Memorial Fund counted 144 federal, state, local, tribal and territorial officers killed. Firearms-related fatalities were the leading cause of officer deaths for the year.[23]
You can check out the sources but they claim 52 shot and killed and 50 in traffic related incidents.