Sharraxaadda

As someone who crosses Independence and First St virtually every weekday, going to work, I have noticed a lot of people traveling east on Independence Avenue who ignore the "No left turn" sign and attempt to turn left onto First Avenue. It looks like taxis/cabs are the worst offenders of this traffic violation. Of course, this rule at this intersection is only in effect during certain daytime hours.

There is a red lighted sign that tells people not to make a left turn, but it is difficult to read during the day when it is activated. Maybe a brighter/more clear sign could be used. It is difficult to tell if people can't read, just don't know or don't care. Are cabs under specific rules to ignore these signs?