Try unplugging the modem for about 5-10 min.. then run the tracert again.. That is way to high for the modem.. I should be between 1ms-3ms..
One other thing.. looking at comcast's help site.. there are know issues in the PA area..King of Prussia, Pa is having problems.
Here is what the forum techs had to say.. they have figured out that there is a problem with over 700 users in the PA, NJ, DE area, they said they are now working on the problem, it will be fixed in under 2 weeks they hope. It might cut down on the amount of people complaining about this issue.
It doesnt look like they are going to make an offical anouncment... however, comcast.net help section then connection.. has all of the details