  Transformation rules for coordinates, velocities and accelerations in
accelerated reference frames are derived. A generalized approach of the special
relativity is taken for a basis. A 7-dimensional space including projections of
velocity vector as three additional coordinates to time and geometric
coordinates is studied. Turns in pseudoplane (dt,dv) of this 7-space describe
accelerated motion of frame. In addition to the light velocity, the
transformation formulas contain a fundamental constant which has a meaning of
maximal acceleration. It is demonstrated that if a source of light moves with
acceleration with respect to some reference frame, the light velocity in this
frame is less than the constant $c$ and depends on acceleration. The special
relativity relation between energy, impulse, and mass gets changed for particle
in accelerated motion. A generalized wave operator being invariant to the above
transformations is introduced. The components of tensor and of potential of
electromagnetic field get intermixing in transformation relations for
accelerated frame.
