Possible Clues:

• This street allows only single traffic flow
• Not allowing reverse motion
• Oh yes, that's about a new sort of street
• Street sign
• There's no going back on it
• Nothing modern ever appears in this kind of street
• This road permits only a single flow of traffic
• Straightforward, not wanting a reciprocal action
• No traffic is met in this street
• Words on an arrow-shaped sign