I want to export this data with 1 km/h steps

One solution to your problem is to use helper cells to perform interpolations:

• In cell K3 enter:
  
  PHP Code: 

  =TEXT(ADDRESS(MATCH(J3,B:B,-1),1,4,1),"#") 

  This will return the address of the time-cell (A100) whose speed (130.051) is just greater than the test speed (130 kmh)
• In cell L3 enter:
  
  PHP Code: 

  =INDIRECT($K3) 

  The time corresponding to 130.051 kmh
• In cell M3, enter:
  
  PHP Code: 

  =OFFSET(INDIRECT($K3),1,0,1,1) 

  The time corresponding to the speed just below the test speed.
• In cell N3:
  
  PHP Code: 

  =OFFSET(INDIRECT($K3),0,1,1,1) 

  The speed just above the test speed
• In cell O3:
  
  PHP Code: 

  =OFFSET(INDIRECT($K3),1,1,1,1) 

  The speed just below the test speed
• in cell P3:
  
  PHP Code: 

  =ROUND(FORECAST($J3,L3:M3,N3:O3),2) 

  The desired interpolated time for the test speed, in this case, 3.91 sec at 130 kmh

Drag the formulas down to the last test row (40 kmh).
You will have to modify the formulas for the last value, since the table does not go below 40 kmh which is required for the FORECAST Function to work properly.