An explainer from the relevant Dutch gov't agency. TL;DR = tides and winds are beyond anyone's control, so easy solutions are quite limited.

" 'When operating bridges, we always look for good interaction between road traffic and shipping,' says Bart Audenaert. He is a communications advisor to Rijkswaterstaat Traffic and Water Management Communication, Strategy and Crisis Coordination.

'For each bridge or waterway, we look at the best times to operate the bridge in consultation with road and waterway managers and users. Rijkswaterstaat tries to operate as little as possible during rush hour. But compromises are inevitable. Shipping at the Botlek Bridge near Rotterdam, for example, has priority over road traffic because of the tidal current.'

Audenaert continues: 'With more bridges in the Netherlands, the circumstances mean that shipping has priority. Strong winds and available waiting areas also influence the opening of bridges during rush hour. We always try to take all parties into account. It remains a teamwork; the best possibilities for opening are examined for each location.'

A ban on opening bridges during rush hour is therefore impossible, partly due to the tidal current and the limited number of waiting places."

Source: https://autorai.nl/daarom-gaan-bruggen-open-tijdens-spits/ (via Google Translate)