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The extragalactic distance scale relies heavily on Cepheids. However, it hasbecome clear from observations and pulsation models that the slope and zeropoint of their P-L relations differ from galaxy to galaxy. This makes thedetermination of Cepheid distances complex and calls for an independent test oftheir differences. The test is provided by RR Lyrae star distances of 24galaxies which calibrate the tip of the red-giant branch (TRGB; M_I = -4.05),which in turn confirms the adopted Cepheids distances on our 2006 distancescale in 18 cases to within 0.1 mag on average. Relative SN Ia and velocitydistances deny a remaining significant metallicity effect of the adopteddistances. The new support for these Cepheid distances increases the weight ofour previous calibration of the SN Ia luminosity and of the 21cm line width -luminosity (TF) relation. The value of H_0 = 62.3 (+/-5) is confirmed on allscales.

Comparison of Distances from RR Lyrae Stars, the Tip of the Red-Giant Branch and Classical Cepheids