TULSA, Oklahoma - The 40th annual Tulsa Federal Credit Union Tulsa Run is Saturday and city workers are busy closing several downtown streets ahead of the event.

Boston Avenue between 4th and 5th Streets will be closed today and it will remain that way until the races are over Saturday afternoon.

The City of Tulsa says the start line will mean the closure of Boulder between 5th and 6th Streets as well.  

Run organizers says they'll be welcoming in runners from over 30 states and eight foreign countries, including Mexico and Japan.

Its signature feature is a 15K run, which stretches from downtown, to west tulsa, to Brookside, but as far as we can tell, they wont be closing any other streets except the start and finish lines.