Fremont Bridge Opening Times

I bike across the Fremont Bridge twice a day which Wikipedia claims is the most frequently opened bridge in the United States. This claim is uncited and while it may be true, due to Federal Maritime Law boats get precedence for bridge opening with the exceptions of rush hours which in Seattle are M-F 7-9 AM and 4-6 PM. I often get to the bridge on my bike around 9 AM in the morning and 6 PM in the evening and it always felt like the bridge opens for a boat right at 9 and 6 PM on the dot. I wanted to verify this and figured the only way to do so would be to manually time the bridge openings but that seemed like too much effort.

Recently, a friend notified me about the twitter account of Seattle DOT bridges which is basically a bot that posts bridge openings and closings such as:

I used the excellent twitteR to scrape tweets from Seattle DOT bridges for the past month to test how accurate my assumption was. From this, I pulled the first crossing post morning rush hour and evening rush hour for weekdays only.

The mean opening time post-morning rush was 9:28 AM and the mean opening time post-evening rush was 6:25 PM which means that my assumptions were pretty off and I should not feel so stressed to arrive at the bridge before 9 AM and before 6 PM.