Line of evidence	Traversette	Clapier	Mont-Cenis	Montgenèvre	Larche	Petit St B.	Grand St B.	Other col
P1 The Island: four days beyond a crossing that is itself four days from the sea, at a confluence with a second river (mss Skaras/Skoras; Sarar/Arar), shaped like the Delta, with the Allobroges next to it	0.25–0.6	0.7–1	0.7–1	0.25–0.6	0.25–0.6	0.7–1	0.6–1	0.4–0.9
P2 Then 800 stades in ten days along the river through flat country, escorted through the Allobroges, to the foot of the ascent	0.3–0.6	0.8–1	0.8–1	0.3–0.6	0.3–0.6	0.7–1	0.05–0.15	0.4–0.9
P3 The first fight is with the Allobroges, at the first defile of the ascent, with their town close by	0.15–0.5	0.8–1	0.8–1	0.15–0.5	0.15–0.5	0.8–1	0.4–0.8	0.3–0.8
P4 Nine days from the foot of the ascent to the summit, with a battle, a captured town, a halt, a second ambush and a night in a gorge	0.6–1	0.8–1	0.8–1	0.6–1	0.6–1	0.8–1	0.5–1	0.5–1
P5 The plains of the Po are pointed out from the summit camp (Polybius) or from a promontory on the first descent morning (Livy)	0.8–1	0.45–0.85	0.1–0.3	0.05–0.2	0.05–0.2	0.05–0.2	0.05–0.2	0.1–0.5
P6 Old snow from the previous winter lies under the new snow on the descent, at the setting of the Pleiades (29 Oct to 9 Nov)	0.8–1	0.25–0.7	0.1–0.35	0.03–0.2	0.05–0.25	0.1–0.35	0.25–0.7	0.2–0.9
P7 The descent is narrow and steeper than the ascent, a cliff-path is broken away for 1.5 stades, and the plain is reached three days below the cliffs	0.8–1	0.8–1	0.4–0.8	0.15–0.4	0.1–0.35	0.1–0.35	0.5–0.9	0.3–0.9
P8 He comes down among the Taurini and by "the pass through the Taurini" (Polybius 3.60.8, 34.10.18; Livy 21.38.5-7), not among the Salassi	0.4–0.75	0.9–1	0.9–1	0.9–1	0.3–0.65	0.05–0.2	0.05–0.2	0.3–0.9
P9 The crossing itself is "about 1,200 stades" (3.39.10) and takes fifteen days	0.7–1	0.4–0.85	0.4–0.85	0.7–1	0.7–1	0.5–0.9	0.3–0.7	0.4–0.9
L1 Livy: from the Island left into the Tricastini, along the Vocontii into the Tricorii, across the Druentia, then a mostly level road to the Alps	0.7–1	0.3–0.6	0.3–0.6	0.7–1	0.7–1	0.3–0.6	0.2–0.5	0.4–0.9
T2 Varro lists Hannibal's pass between the coast road and Pompey's; Pompey says his own route was "other than Hannibal's"	0.7–1	0.35–0.8	0.35–0.8	0.15–0.45	0.7–1	0.15–0.5	0.2–0.6	0.5–1
T3 The Roman tradition Livy rejects: Coelius's Cremonis iugum, the popular Poeninus, Nepos's saltus Graius	0.4–0.8	0.4–0.8	0.4–0.8	0.4–0.8	0.4–0.8	0.7–1	0.6–1	0.4–0.8
G1 The Traversette mire and rockfall (Mahaney and colleagues 2010-2026)	1–1	0.75–1	0.75–1	0.75–1	0.75–1	0.75–1	0.75–1	0.75–1
F1 Practicable in early November for 30,000 men, thousands of animals and 37 elephants, and known as a route (Polybius 3.48.6: Gallic armies had crossed before)	0.2–0.6	0.5–0.9	0.9–1	0.9–1	0.9–1	0.9–1	0.7–1	0.3–0.9
Headline run (Polybian items at half strength)	29%	40%	16%	1%	3%	2%	<1%	9%
Full model (every item at full strength)	19%	70%	8%	<1%	<1%	<1%	<1%	3%