Clause 2.5.2.6.2 of AASHTO LRFD Bridge Design Specification 8th Edition recommends the following deflection limits:

Load case

Max deflection

Traffic only

\(L/800\)

Traffic + pedestrian

\(L/1000\)

Traffic on cantilever arms

\(L/300\)

Traffic + pedestrian on cantilever arms

\(L/375\)

where \(L\) is the span length.

BS 5400-3:2000

Clause 5.7 of BS 5400-2:2000 Code of practice for design of steel bridges recommends that, for aesthetic purposes, a bridge should not sag more than \(L/800\) below horizontal (i.e. \(L/800\) plus any precamber) where \(L\) is the span length.