The complex conductivity spectra of the quasi-one-dimensional compounds

K_{0.3}

{MoO}_{3}

(blue bronze) and (

{TaSe}_{4}

)_{2}

I in the conducting phase (above

T_{3 D}

=183 K and 263 K, respectively, but below the mean-field temperature

T^{MF}

) have been measured over a broad frequency range, 1–

10^{5}

{cm}^{- 1}

, using a combination of different spectroscopic techniques; we have also investigated the effects of disorder. Clearly pronounced excitations are discovered in the spectra below 50

{cm}^{- 1}

for the electric field E→ parallel to the chains, the direction along which the charge-density wave develops below the Peierls transition temperature

T_{3 D}

. We associate these excitations with charge-density-wave fluctuations that exist even at room temperature and result in a collective contribution to the conductivity. For the transverse polarization, E→ perpendicular to the chains, no such low-frequency excitations are evident in the conductivity spectra. These measurements give clear evidence for important deviations from conventional metallic behavior in the fluctuating region below

T^{MF}

but above

T_{3 D}

, the temperature where three-dimensional long-range order develops.

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