Traffic Jam solution
by Kegler

Nine entries each direction contain vehicles “jammed” into one square.  These are indicated by numbers in the red squares in the diagram:
1=CAB, 2=AUTO, 3=RIG, 4=LIMO, 5=VAN, 6=CAR, 7=BUS, 8=SEMI, 9=TRUCK.

Traffic Jam solution grid

Across
1CA + T + SPA + W
6MACAw + BREd
10T + AU(TO)G
12A + LIEN
13COLA (hidden)
14A + BOR(I + GIN)ES
15JU + DO
17SKI (hidden)
18INGLE (NIGEL anag)
19MILL + I'M + OLE
21S(A + Y)INGS
23NICE (2 defs)
25DI + VAN (I'D rev)
27BO(S + S)Y
29APOTHECARY (REACH TO PAY anag)
31HE(M)'S
33GEN(I)US
36AM + B + US + H
37DISSEMINATE (SEED MAN IT IS anag)
40S(I)TOUT
41STONE + D (NOTES anag)
42T(R)UCK + LING
43FEINTS ("FAINTS" hom)
Down
1C + ACT I
2TAUT + O + LOGY
3P(E)A
4AL + BUM
5WOO + D
6MAR(I + G + OLD)S
7CA(B)IN'S
8REEK (hidden)
9ENSILED (LINSEED anag)
10T + OWN
11GALL + IVAN + T
16ALI + MONeY
20L + IKE
21ST(AGES + TR)UCK
22GOrES
24COMB + US + T
26I(O)NS
28SCAR + E
30YOSEMITE (rev hidden)
31H(AN + O)I
32SHEDS (2 defs)
34E(V)IL (LIE rev)
35IRON (FElt, atomic symbol for iron)
38ITS (SIT anag)
39AN + N