the women's march on washington is set to begin in a few minutes. they're getting started in a few cities around the country. i want to bring in cnn's law enforcement analyst, police chief charles ramsey who is joining us after yoed's violent clashes in washington. chief, how does the city like washington, d.c., prepare? because potentially there could be some more, what, a few hundred people were arrested yesterday. >> about 230 were arrested yesterday. but today will be totally different. the biggest challenge is going to be crowd control and traffic control. because when you have large numbers of people you obviously have to reroute traffic around them. that's the biggest challenge for police. i think today will be a very peaceful demonstration unlike a very few number of people. >> what happened yesterday? why did it get so ugly? >> you had some people that came with the intent of causing problems. i don't even call them demonstrators. i don't give them the honor of being a demonstrator. they're folks that came in to commit acts of vandalism.