We design a laboratory experiment that allows for testing unregulated selfish route
choice behavior in a road pricing environment where the introduction of a road toll may
generate network effects or excess burdens that are known from Braess’s Paradox. We
consider three alternative treatments: no tolls (NOT), a Braess’s Paradox generating toll
(BPT), a maximum toll that does not generate Baress’s Paradox (MAT). Among other things,
our results indicate that the actual excess burden generated by the BPT-treatment is
significantly higher than the excess burden generated by either the NOT- or MAT-treatment.
We therefore conclude that road tolls should not exceed the MAT level. To this extent, our
findings have important implications for the optimal design of road pricing schemes.