At this point, it doesn't look like anyone's showing up for the parade [Updated with Cameras on the Ground] [View all]
Update: The AP has a split screen with 4 separate camera views. The lower right one does at times seems to show a decent crowd but they seem to be packed into a really small area. The mall camera looks like any Saturday in Summer - people wandering around though some people are understandably curious to see a tank up close. The upper right is the reviewing stand, which seems rather small and there doesn't appear to be much of anyone else around that area - like they're keeping it clear for security purposes.
Update 2: the lower right camera now seems to be showing a small group of peaceful protestors.
https://www.google.com/search?q=live+coverage+of+parade+from+DC+news&rlz=1C1SJWC_enUS1101US1101&oq=live+coverage+of+parade+from+DC+news&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigATIHCAMQIRigATIHCAQQIRigATIHCAUQIRigAdIBCjEyMTIyajBqMTWoAgqwAgHxBWm17UbzoP5n&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:5afc0a0e,vid:aWBUbqYDbVA,st:0
The one live webcam I can find is from the top of the Washington Monument. The clarity isn't great, but you can see people moving around on the ground. The Parade route is on Constitution Avenue - the street on the right running parallel to the reflecting pool.
It doesn't look like there are any significant crowds lining the street.
?v=d2f497bd9339ad99d2e0559414346698
Link to webcam:
https://www.earthcam.com/usa/dc/washingtonmonument/?cam=wamo