Overhead signs on freeways: Are drivers being told too much? The growing trend to install multiple road signs at the same location along Australian freeways might be practical and cost-effective but is it safe? A new study has looked at the impact of locating up to three signs on a freeway gantry (Bridge-like overhead structure) and found driving performance is not affected and drivers are able to respond safely to an emergency situation. Source 9p.
The information as long as it is clear and short can help drivers get the info they need. Also the more warning you can give a person helps a lot to allow the driver to adjust their speed and lanes as needed in a safe way.