Minimum Curve Radius Equation Error?

[Mizza]

While calculating a problem to solve for the minimum horzontial curve radius I noticed that the equation I used out of the Green Book (eq 3-10) was different than that used in the solution. I looked in some other books (CERM and Traffic and Highway Engineering 4th ed.) and noticed a difference. The Green book muliplies e by 0.01 and the other books do not. Here are the equations:

Green Book (eq 3-10) Rmin = (V^2)/(15(0.01emax + fmax))

Traffic and Highway Engineering 4th ed. (eq. 3.33) Rmin = (V^2)/(15(emax + fmax))

The solution to the problem uses the equation: Rmin = (V^2)/(15(emax + fmax))

So my question is: Which one is correct?

Thank you in advance.

 

[sac_engineer]

While calculating a problem to solve for the minimum horzontial curve radius I noticed that the equation I used out of the Green Book (eq 3-10) was different than that used in the solution. I looked in some other books (CERM and Traffic and Highway Engineering 4th ed.) and noticed a difference. The Green book muliplies e by 0.01 and the other books do not. Here are the equations:
Green Book (eq 3-10) Rmin = (V^2)/(15(0.01emax + fmax))

Traffic and Highway Engineering 4th ed. (eq. 3.33) Rmin = (V^2)/(15(emax + fmax))

The solution to the problem uses the equation: Rmin = (V^2)/(15(emax + fmax))

So my question is: Which one is correct?

Thank you in advance.

It's the same equation, but you must ensure that emax is in decimal, not percent. Ignore the "0.01" factor and always use the decimal equivalent of emax. If the problem statement gives you emax as a percent value (e.g. 4%), use the decimal value (e.g. 0.04) to avoid confusion of whether you need to multiply emax by 0.01.

Good luck!

 

[Mizza]

That makes sense. Thank you for the explanation.