NO HORSES ARE ALLOWED ON THE BRIDGE. PERIOD.
This means no horses at all, whether they are being led or ridden. Signs are now posted to this effect. Violators will be fined.
If you encounter horses on the High Trestle Bridge, call the Boone County Conservation Director, Andy Hockenson, 515-353-4237, for issues in Boone County (most of the sections between Woodward, Madrid and Slater including the bridge, except for Slater mile to a mile west (Story County) and Woodward to a mile east (Dallas County). Sheldahl to Ankeny is Polk County Conservation 515-323-5300. (Of course in emergencies call 911.)