# [Japt] `-R`, 40 bytes

    Æ=Vg"|\\/";²i1S+iX%2?S:U)iSp[TZÊ-YY]gVÃw

[Try it online!][TIO-jt67pot4]

### Explanation:
    Æ=Vg"|\\/";²i1S+iX%2?S:U)iSp[TZÊ-YY]gVÃw
                                                // U = road size
                                                // V = direction
    Æ                                     Ã     // Loop X through [0...U]
     =        ;                                 //   Set U to:
        "|\\/"                                  //       "|\/"
      Vg                                        //            [V]
               ²                                //  Double U
                i1          )                   //  Insert at index 1:
                  S+                            //    " " +
                     X%2?S:U                    //         X%2?" ":U
                    i                           //                  + " "
                             i                  //  Insert at index 0:
                              Sp                //    " " repeated this many times:
                                [TZÊ-YY]        //      [0,U.length - X,X]
                                        gV      //                        [V]
                                            w   // Reverse output
          
      

[Japt]: https://github.com/ETHproductions/japt
[TIO-jt67pot4]: https://tio.run/##y0osKPn//3CbbVi6Uk1MjL6S9aFNmYbB2pkRqkb2wVahmpnBBdEhUYe7dCMjY9PDDjeX//9voaNgyMWlGwQA "Japt – Try It Online"