sample data available here: http://www.state.nj.us/transportation/refdata/accident/2013/Monmouth2013Accidents.zip
Offending line (767 in linked file) has the following value: ""A"" ST
Compare to read.table:
f <- "Monmouth2013Accidents.txt"
ans1 <- fread(f)
ans2 <- as.data.table(read.table(f, header=FALSE, sep=",", comment.char="", quote="", stringsAsFactors=FALSE))
dim(ans1)
# [1] "766 rows X 47 cols"
dim(ans2)
# [1] "20,700 rows X 47 cols"`
possibly related to #1077.