Coupled transcription and translation is considered a defining feature of bacterial gene expression
1
,
2
. The pioneering ribosome can both physically associate and kinetically coordinate with the RNA polymerase (RNAP)
3
-
11
, forming a signal-integration hub for co-transcriptional regulation that includes translation-based attenuation
12
,
13
and RNA quality control
2
. However, whether transcription-translation coupling – together with its broad functional consequences – is indeed a fundamental characteristic outside the well-studied
Escherichia coli
remains unresolved. Here we show that RNAPs outpace pioneering ribosomes in the Gram-positive model bacterium
Bacillus subtilis
, and that this ‘runaway transcription’ creates alternative rules for both global RNA surveillance and translational control of nascent RNA. In particular, uncoupled RNAPs in
B. subtilis
explain a diminished role of Rho-dependent transcription termination, as well as the prevalence of mRNA leaders that utilize riboswitches and RNA-binding proteins. More broadly, we identified widespread genomic signatures of runaway transcription in distinct phyla across the bacterial domain of life. Our results demonstrate that coupled RNAP-ribosome movement is not a general hallmark of bacteria. Instead, translation-coupled transcription and runaway transcription constitute two principal modes of gene expression that determine genome-specific regulatory mechanisms in prokaryotes.