Corner fillet

The corner fillet is a design element when planning junctions on roads. Two intersecting road edges are connected with a fillet. In this way, the drivability for the vehicle driver turning in or out is guaranteed with a uniform steering movement.

A simple circular arc is used to round off subordinate streets. On the other hand, a three-part circular arc sequence (so-called basket arch) is used on roads with more traffic. This rounding corresponds most closely to the drag curve of motor vehicles. The size of the corner fillet generally depends on the measurement vehicle .

The radius ratio for a three-part circular arc sequence is:

${\displaystyle R_{\mathrm {1} }:R_{\mathrm {2} }:R_{\mathrm {3} }=2:1:3}$

The starting radius R ₁ has a change in direction of 17.5 gon and the end radius R ₃ of 22.5 gon. The remaining change of direction takes place through the main arch R ₂ . The main curve radius R ₂ on city streets is usually 8 m for one-turners and 12 m for turn-offs. According to RAL 2012, a main curve radius of 12 m for access roads (access type KE6 only 10 m) and 15 m for turns (right-turn type RA6 only 12 m) must be selected for country roads.

Web links

• Information on corner fillets at junctions ( Memento from July 5, 2015 in the Internet Archive ) (PDF file; 767 kB) see p. 12

Individual evidence

1. ^ Gerd Steierwald: Urban traffic planning . Basics, methods, goals. Springer Verlag , 2005, ISBN 3-540-40588-7 , p. 528 (on Googlebooks)
2. ↑ Preliminary specifications for the structural design of roundabouts - KVP (PDF file; 114 kB) Status: July 1st, 2005, on the website of the Saxony-Anhalt Political and Administrative Library
3. ↑ Otto W. Wetzell (Ed.): Wendehorst examples from building practice. Vieweg + Teubner , Wiesbaden 2009, ISBN 978-3-8348-0684-0 , pp. 522-523 (on Googlebooks)
4. ↑ FGSV (Ed.): Guidelines for the layout of city streets (RASt) . Cologne 2006, p. 123 .