I'm a consultant for traffic managent in the UK. A lot of old neighbourhoods weren't originally designed to accommodate cars, so we can learn from their mistakes by studying how others did it. Long before the internal combustion engine dictated urban layout, narrow, winding, and twisting roadways were created. As an added bonus, these layouts reduce vehicle speeds; there's no need for elaborate man-made measures when nature can accomplish the task just fine. Maintain fidelity to the original urban plan while making minor adjustments to meet modern demands; make do with what you have.