I think laws are made on cultural and religious backgrounds.?One cannot pick and choose implementation of laws based on cultural preferences - such as causing other muslims and humans inconvenience and saying its not a big deal:
Anyway, road blocking mustn't be encouraged as Namaz becomes makroh. Here in UK, on Sunday, some car parks and roads are converted to open market for entire day. So exception can be made for Jumma too. But mosques shoudl take permission as the open markets have that. So, govt can allow the streets but not the main road.